12.A) Mary has a keen eye for style.

　　B) Nancy regrets buying the dress.

　　C) Nancy and Mary went shopping together in Rome.

　　D) Nancy and Mary like to follow the fashion.

　　M：How does Nancy like the new dress she bought in Rome?

　　W：She said she would never have bought an Italian style dress if she had known Mary had already got such a dress.

　　Q：What do we learn from the conversation?

　　B)。四个选项中多次提到Nancy和Mary，还出现了style, dress, fashion等词，所以推测本题可能涉及两人的某件服装款式。对话中男士打听Nancy是否喜欢新买的衣服，女士回答到，Nancy说如果她知道Mary已经有一件这样款式的衣服，她绝对不会买的。结合生活实际，任何人都想买一件与众不同的衣服，可见Nancy后悔自己买了一件与别人同样款式的衣服。故答案为B)。