(a) As used in this Code section, the term:

(1) "Active duty" means full-time duty in the United States armed forces, other than active duty for training, for a period of more than 90 consecutive days.

(2) "Active duty for training" means full-time duty in the United States armed forces for a period of more than 90 consecutive days for training purposes performed by members of the National Guard and Air National Guard who are residents of this state.

(3) "Qualified life insurance" means insurance coverage through the Servicemembers' Group Life Insurance Program administered by the United States Department of Veterans Affairs for the maximum benefit amount available under such program for the loss of life of a member of the National Guard or Air National Guard who is a resident of this state while on active duty or active duty for training.

(b) A taxpayer shall be allowed a credit against the tax imposed by Code Section 48-7-20 in an amount not to exceed the amount expended for qualified life insurance premiums.

(c) The credit provided under this subsection:

(1) Shall be claimed and allowed in the year in which the majority of such days are served. In the event an equal number of consecutive days are served in two calendar years, then the exclusion shall be claimed and allowed in the year in which the ninetieth day occurs; and

(2) Shall apply with respect to each taxable year in which such member serves for such qualifying period of time.

(d) In no event shall the total amount of the tax credit under this Code section for a taxable year exceed the taxpayer's income tax liability. Any unused tax credit shall be allowed the taxpayer against succeeding years' tax liability. No such credit shall be allowed the taxpayer against prior years' tax liability.

(e) The commissioner shall be authorized to promulgate any rules and regulations necessary to implement and administer the provisions of this Code section.