根据上下文的意思，选择恰当的句子补全对话。

A. Where are the hens? B. Are they horses? C. What are they? D. Yes, I do. E. How many horses do you have?

A：Hello! Welcome to the farm.

B：Oh, this farm is so big!

A：Yes, they are.

B：

A：We have twenty.

B：

A：They are potatoes.

B：Do you like potatoes?

A：

B：

A：They are under the tree.