Subject to the provisions of this Article on breach in installment contracts (section 554.2612) and unless otherwise agreed under the sections on contractual limitations of remedy (sections 554.2718 and 554.2719), if the goods or the tender of delivery fail in any respect to conform to the contract, the buyer may
 1. reject the whole; or
 2. accept the whole; or
 3. accept any commercial unit or units and reject the rest.