David Singer, my friend's father,______raised and educated in New York, lived and lectured in Africa most of his life.

A. who       B. if      C. though     D. while

though 引导让步状语从句时，如果从句主语与主句主语相同，且从句谓语含有动词be, 则可以省略从句的主语和be. 本句though 从句就是省略了 he was. 如果不省略则为：

David Singer, my friend's father, though he was raised and educated in New York, lived and lectured in Africa most of his life.