—Are there any balls under the chair?—. A. Yes there is B. Yes they are C. Yes there

问题补充：

—Are there any balls under the chair?—.

A. Yes, there is B. Yes, they are C. Yes, there are

答案：

解析：问句文的是椅子下面有球吗？答语中应用there那儿，代替问句中提到的位置短语，并且人称和数要与问句保持一致，所以选C。