It is said in the book that Tomas Edison __________ the world leading inventor for sixty years.

It is said in the book that Tomas Edison __________ the world leading inventor for sixty years.
A.would be B.has been C had been D was
-George and Lucy got married last week .Did you go to their wedding?
-No,I ___________.Did they have a big wedding?
A.was not invited B.have not been invited
C.hadn't been invited D.didn't invite
C 我选的是C 请问这该怎么区分
for sixty years 要用完成时吗