Choice "A" is correct. The Sales Article applies to all contracts for the sale of goods, regardless of price. Choice "d" is incorrect. All parties are bound by the obligation of good faith under the UCC.
Choice "b" is incorrect. The presumption is that all sales are final. A sale or return or sale on approval (both of which allow the return of the goods) is available only if the parties so provide.
Choice "c" is incorrect. The Sales Article covers all sales of goods. If the purchase price is $500 or more, a writing may be required to enforce the contract under the Sales Article's Statute of Frauds, but the Sales Article still applies.