Collecting stamps as a hobby___________ increasingly popular during the past fifty years.

A. becomes         B. became        C. has become     D. had become

Collecting stamps as a hobby___________ increasingly popular during the past fifty years.

A. becomes         B. became        C. has become     D. had become

Collecting stamps as a hobby___________ increasingly popular during the past fifty years.

A. becomes         B. became        C. has become     D. had become

Collecting stamps as a hobby___________ increasingly popular during the past fifty years.

A. becomes         B. became        C. has become     D. had become

Collecting stamps as a hobby___________ increasingly popular during the past fifty years.

A. becomes　　　　 B. became　　　 C. has become　　 D. had become