(a) That's wrong. In this example, it is clear that A did not offer to buy any Oldfield desk, but the particular one he saw and liked. B accepted this offer and the sale is therefore a sale of specific goods. In such cases the seller is obliged to deliver those very goods: no others will do, even if they seem the same. This can be important when specific goods have characteristics which are significant to, or appeal to, the buyer, such as the particular appearance of a piece of furniture, or the quality of particular goods.
NOTE: Provided that specific goods are inspected when bought, the seller is not obliged to guarantee that the goods are of a particular quality.