(a) Unless otherwise agreed, tender of payment is a condition to the seller's duty to tender and complete a delivery.
(b) Tender of payment is sufficient when made by a means or in a manner current in the ordinary course of business unless the seller demands payment in legal tender and gives an extension of time reasonably necessary to procure it.
(c) Subject to the provisions of the code on the effect of an instrument on an obligation (AS 45.03.310), payment by check is conditional and is defeated as between the parties by dishonor of the check on due presentment.