(a) The plan may pay the reserve value of any annuity benefit to a retirant or beneficiary when the annuity benefit payment is less than twenty dollars ($20.00) per month, except that the consent of the payee shall be required if the payment exceeds one thousand seven hundred fifty dollars ($1,750).
(b) The reserve value shall be the actuarial equivalent of the annuity otherwise payable.
(c) Any lump-sum payment so made shall be a complete discharge of all liability under the plan with respect to the annuity.