(a) "Acceptance" means the drawee's signed agreement to pay a draft as presented. It must be written on the draft and may consist of the drawee's signature alone. Acceptance may be made at any time and becomes effective when notification pursuant to instructions is given or the accepted draft is delivered for the purpose of giving rights on the acceptance to any person.
(d) "Certified check" means a check accepted by the bank on which it is drawn. Acceptance may be made as stated in subsection (a) or by a writing on the check which indicates that the check is certified. The drawee of a check has no obligation to certify the check, and refusal to certify is not dishonor of the check.