volleyball is her main focus she’s also great at basketball.A Since B. Once C. Unless D.

问题补充：

volleyball is her main focus, she’s also great at basketball.

A Since B. Once C. Unless D. While

答案：

解析：考查从属连词。尽管排球是她的中心，她也擅长篮球。while引导让步状语从句。