The old professor to the important invention decided not to keep it for himself but to

问题补充：

The old professor, to the important invention , decided not to keep it for himself, but to make it known to all over the world.

A. whom; was belonged

B. which; belonged

C. whom; belonged

D. which; was belonged

答案：

A. whom; was belonged

B. which; belonged

(答案→)C. whom; belonged

D. which; was belonged

解析：考查定语从句。句中先行词为professor，在从句中作宾语，故用关系词whom；belong to属于，不及物词组，无被动形式，故选C。