(b) The proceeds of any such bonds issued for the purpose of refunding outstanding bonds may, in the discretion of the board, be applied to the purchase or retirement at maturity or redemption of such outstanding bonds either on their earliest or any subsequent redemption date or upon the purchase or at the maturity thereof and may, pending such application, be placed in escrow to be applied to such purchase or retirement at maturity or redemption on such date as may be determined by the board.
(c) Any such escrowed proceeds, pending such use, may be invested and reinvested in direct obligations of the United States of America, maturing at such time or times as are appropriate to assure the prompt payment of the principal of and interest and redemption premium, if any, on the outstanding bonds to be so refunded. The interest, income and profits, if any, earned or realized on any such investment may also be applied to the payment of the outstanding bonds to be so refunded. After the terms of the escrow have been fully satisfied and carried out, any balance of such proceeds and interest, income and profits, if any, earned or realized on the investments thereof shall be returned to the institution of higher education for use by it in any lawful manner.
(d) All such refunding bonds are subject to this article in the same manner and to the same extent as other revenue bonds issued pursuant to this article.