Section 4. For 120 days after the expiration of affordability restrictions on housing assisted under this section, the department or its assignee, who is a qualified developer selected pursuant to the terms of this section under the guidelines of the department, shall have an option to purchase that property at its current appraised value, less any remaining obligations of the owner upon the expiration of the affordability restrictions. The department or its assignee may purchase or acquire the housing only for the purposes of preserving or providing affordable housing. Failure to exercise the purchase option within the 120–day period shall constitute a waiver of the purchase option by the department or its assignee. Two impartial appraisers shall determine, within 60 days after the expiration of the affordability restrictions, the current appraised value in accordance with recognized professional standards. Two professionals in the field of multi-unit residential housing shall each select an appraiser. The owner and the department, respectively, shall each designate a professional within 30 days after the expiration of the affordability restrictions. If there is a difference in the valuations, the valuations shall be added together and divided by 2 to determine the current appraised value of the property. No sale, transfer or other disposition of the property shall be consummated until either the purchase option period shall have expired or the owner shall have been notified, in writing, by the department or its assignee that the option will not be exercised. The option shall be exercised only by written notice signed by a designated representative of the department or its assignee, mailed to the owner by certified mail at the address specified in the notice of intention and recorded with the registry of deeds or the registry district of the land court of the county in which the affected real property is located, within the option period. If the purchase option has been assigned to a qualified developer selected pursuant to this section, the written notice shall state the name and address of the developer and the terms and conditions of the assignment. Before any sale or transfer or other disposition of the housing where the department has not previously exercised an option to purchase, an owner shall offer the department or its assignee, who shall be a qualified developer selected pursuant to this section, a first refusal option to meet a bona fide offer to purchase the property. The owner shall provide to the department or its assignee written notice by regular and certified mail, return receipt requested, of the owner's intention to sell, transfer or otherwise dispose of the property. The department or its assignee shall hold such the refusal option for the first 120 days after receipt of the owner's written notice of intent to transfer the property. Failure to respond to the written notice of intent to sell, transfer or otherwise dispose of the property within the 120–day period after the receipt thereof shall constitute a waiver of first refusal option by the department. No sale, transfer or other disposition of the property shall be consummated until either the first refusal option period shall have expired or the owner shall have been notified in writing by the department or its assignee that the option will not be exercised. The option shall be exercised only by written notice signed by a designated representative of the department or its assignee, mailed to the owner by certified mail at the address specified in the notice of intention and recorded with the registry of deeds or the registry district of the land court of the county in which the affected real property is located, within the option period. If the first refusal option has been assigned to a qualified developer selected pursuant to this section, the written notice shall state the name and address of the developer and the terms and conditions of the assignment. An affidavit before a notary public that the notice of intent was mailed on behalf of the owner shall conclusively establish the manner and time of the giving of notice the affidavit and notice that the option shall not be exercised shall be recorded with the registry of deeds or the registry district of the land court of the county in which the affected real property is located. Each notice of intention, notice of exercise of the purchase option or first refusal option and notice that the purchase option or first refusal option shall not be exercised shall contain the name of the record owner of the property and as reasonable description of the premises to be sold or converted and each affidavit, signed before a notary public, shall have attached to it a copy of the notice of intention to which it relates. The notices of intention shall be mailed to the relevant parties in the care of the keeper of records for the party in question. Upon notifying the owner in writing of its intention to exercise its purchase option or first refusal option during the 120–day period, the department or its assignee shall have an additional 120 days, beginning on the date the purchase option period or first refusal option period expires, to purchase the property. Those time periods may be extended by mutual agreement between the department or its assignee and the owner of the property. Any extension agreed upon shall be recorded in the registry of deeds or the registry district of the land court of the county in which the affected real property is located. Within a reasonable time after requesting an extension, the owner shall make available to the department or its assignee any information that is reasonably necessary for the department to exercise its options.