It is not rare in that people in fifties are going to university for further educationA.

问题补充：

It is not rare in that people in fifties are going to university for further education．

A. 90s ; the

B. the 90s; /

C. 90s; their

D. the 90s ; their

答案：

A. 90s ; the

B. the 90s; /

C. 90s; their

(答案→)D. the 90s ; their

解析：考查数词及代词。In the 90s在90年代；in one’s fifties在某人50多岁时。句意：在90年代50多岁的人很少能够进入大学继续深造。