Choice "A" is correct. Under Article 2 of the UCC the implied warranty of merchantability may be disclaimed in a number of ways. One such way is by the use of an oral statement that mentions merchantability.
Choice "c" is incorrect. Under the UCC the implied warranty of merchantability can only be given where the seller is a "merchant" of goods. The buyer may be a merchant or a non-merchant.
Choice "d" is incorrect. This answer concerns the implied warranty of "fitness" and not merchantability. The warranty of merchantability mainly is a warranty that the goods are fit for ordinary purposes.
Choice "b" is incorrect. An "express" warranty must be part of the basis of the bargain; this is not true of the "implied" warranties.