(1) By reason of the insolvency of the taxpayer, the tax collector or tax commissioner could not by ordinary care and diligence collect the tax;
(2) The tax collector or tax commissioner with ordinary diligence issued execution and placed it in the hands of the sheriff or other officer having power to levy the execution, and that failure to realize the money on the execution was due to no fault of the tax collector or tax commissioner;
(3) The failure to collect the taxes promptly was due to obedience to instructions from the commissioner as to state taxes or from the county governing authority as to county taxes; or
(4) He was prevented from the collection of the taxes by legal proceedings.