答案：C

题目分析：句意：——你好，是哪位在讲话？——你好，我是玲玲。A. who is that over there 那边那个人是谁？B. who is it 它是谁？C. who’s that speaking  是哪位在讲话？      D. who are you你是谁？用于打电话this/that is sb. speaking表示我/你正在打电话。故选C。