My most famous relative of all, who really left his mark on America, was Reb Sussel, my g

My most famous relative of all, who really left his mark on America, was Reb Sussel, my great-grandfather.
A. one
B. the one
C. he
D. someone

A. one(答案→)B. the oneC. heD. someone解析：考查替代词。由语境可判断是特指，且作My most famous relative of all的同位语，用the one。

这下我知道了