(C) The obligations may have the great seal of the state or a facsimile thereof affixed thereto or printed thereon and shall be executed by the treasurer of state or such other executive officers of the state as are designated in the bond proceedings, provided that, consistent with section 9.96 of the Revised Code, all but one of such signatures on obligations, whenever issued, may be facsimile signatures. Any coupons pertaining to obligations shall bear the facsimile signature of the individual officer or officers as is designated in the bond proceedings. Any obligations or coupons may be executed by an individual who, on the date of execution, is the proper officer although on the date of such bonds or coupons such person was not the proper officer. In case any officer whose signature or a facsimile of whose signature appears on any such obligation or coupon ceases to be such officer before delivery thereof, such signature or facsimile is nevertheless valid and sufficient for all purposes as if the officer had remained such officer until such delivery; and in case the great seal of the state has been changed after a facsimile of the seal has been imprinted on such obligations, such facsimile seal shall continue to be sufficient as to such obligations and obligations issued in substitution or exchange therefor. All obligations are negotiable instruments and securities under Chapter 1308. of the Revised Code, subject to the provisions of the bond proceedings as to registration. The obligations may be issued in coupon or in registered form, or both, as the issuing authority determines. Provision may be made for the registration of any obligations with coupons attached thereto as to principal alone or as to both principal and interest, their exchange for obligations so registered, and for the conversion or reconversion into obligations with coupons attached thereto of any obligations registered as to both principal and interest, and for reasonable charges for such registration, exchange, conversion, and reconversion.