When such subscription shall become due and payable, as provided in §65-7-112, the county or city or town making the subscription shall make and execute its coupon bonds for the amount of such subscription, payable not more than twenty (20) years after date, and bearing interest at such rate as may be agreed upon, payable semiannually, and deliver the same to the railroad company; provided, that such county, city, or town may pay such subscription in cash at maturity, if it shall so elect.