It's not rare in ______that people in______fifties are goning to university for further education.It's not rare in ______that people in______fifties are goning to university for further education.A .90s,the B.the 90s,/ C.90s ,their D.the90s选哪一

It's not rare in ______that people in______fifties are goning to university for further education.It's not rare in ______that people in______fifties are goning to university for further education.A .90s,the B.the 90s,/ C.90s ,their D.the90s选哪一
It's not rare in ______that people in______fifties are goning to university for further education.
It's not rare in ______that people in______fifties are goning to university for further education.
A .90s,the B.the 90s,/ C.90s ,their D.the90s
选哪一个呢?为什么?

It's not rare in ______that people in______fifties are goning to university for further education.It's not rare in ______that people in______fifties are goning to university for further education.A .90s,the B.the 90s,/ C.90s ,their D.the90s选哪一
这道题是99年上海高考第6题
It is not rare in ________ that people in ________ fifties are going to university for further education.（99上海6）
A.90s … the B.the 90s … / C.90s … their D.the 90s …their
答案是D.the 90s …their
in the 90s 在90年代 in their fifties 在他们50岁期间

我觉得应该这样做，前面一个是the 90s，后面一个是their，可是你的选项里没有，那就没办法了！！