atongmu

答案应该是C，OG里面有这道题目。C中的do是代替do sell，与前面的不定式priced to sell对应。
附上OG的官方解释：In choice C, the best answer, do is correctly used in place of the full verb do sell; in this verb, do is a conjugated form and sell is in the infinitive form, corresponding to its previous use in the sentence (in the phrase priced to sell). In choice A, the omitted word is selling; in B, D, and E, it is sold. Neither of these forms corresponds properly to to sell earlier in the sentence. Also, in E, the past perfect had been priced signifies that the wines had been priced to sell before the prices were cut.

atongmu

OG的解释没有问题。do的确可以代替省略的不定式，这是一种正确用法。