a. Any member of the retirement system who is credited with at least two full years of teaching service rendered in the state since he last became a member may claim such uncredited prior service as set forth in (2), (3), (4) and (5) of paragraph a of subdivision two of this section, pursuant to subdivision five of this section by paying to the retirement board four per centum of the salaries earned for the years claimed and such uncredited prior service as set forth in (1) of paragraph a of subdivision two of this section by paying to the retirement board the amount he would have been required to contribute at the time such service was rendered, not to exceed four per centum of the salaries earned for the years claimed. The amount due, if any, for such service shall be deposited with the retirement board prior to retirement in accordance with the requirements of this article and the regulations of the retirement board. The retirement board, upon verification of the claim and payment made, shall credit such member with such service. Notwithstanding any other provision of this paragraph, any member who last joined the retirement system prior to July twenty-seventh, nineteen hundred seventy-six and who did not receive credit with the retirement system prior to July first, nineteen hundred eighty-eight for prior service, may obtain credit for prior service pursuant to the provisions of this section or pursuant to the provisions of subdivision b of section four hundred forty-six of the retirement and social security law, whichever is applicable, without making the payments required by this paragraph.