(B) A member of the state teachers retirement system participating in the STRS defined benefit plan who does both of the following may purchase credit under section 3307.70 of the Revised Code for service as a school board or governing board member, other than service subject to the tax on wages imposed by the "Federal Insurance Contributions Act," 68A Stat. 415 (1954), 26 U.S.C.A. 3101, as amended, if the member is eligible to retire under this chapter or will become eligible to retire as a result of purchasing the credit:

1. (1) Agrees to retire within ninety days after receiving notice of the additional liability under division (C) of this section;
2. (2) Provides evidence satisfactory to the state teachers retirement board of service as a school board or governing board member during the years for which the member wishes to purchase credit. Credit may be purchased for service as a school board or governing board member between September 1, 1920, and the first day of January of the year in which the credit is purchased. A member is eligible to purchase one-quarter of a year's credit for each year of service as a school board or governing board member.