§ 140-a. Stock option plans. Subject to such regulations and restrictions as may be prescribed by the superintendent, every bank and every trust company may grant options to purchase authorized and unissued shares of its capital stock to officers, directors and employees, for a consideration as authorized by section five thousand four of this chapter of not less than one hundred per cent of the fair market value of the shares on the date the option is granted, pursuant to the terms of a stock option plan which has previously been adopted by the board of directors of the bank or trust company and approved by the holders of a majority of the outstanding shares of capital stock of the bank or trust company and by the superintendent. Stock options issued hereunder shall not extend beyond a period of ten years from date of issuance.