时态？？！！。。

天使追梦

Radiocarbon dating of fossils taken from caves on islands along southeastern Alaska’s coast suggest that at least a portion of the area was remaining ice-free during the last ice age.

A.suggest that at least a portion of the area was remaining

B.suggest at least a portion of the area remaining

C.suggests that at least a portion of the area remained

D.suggests at least a portion of the area that had remained

E.suggests at least a portion of the area to have remained

during the last ice age.不是该用完成时吗？？？不解不解很不解。。求助~

天使追梦

ding!