Geologists believe that the Bering land bridge, over which human beings are thought to have first entered
the Americans, disappeared about 14,000 years ago when massive glaciers melted and caused the sea level to rise several hundred feet worldwide.
(A) are thought to have first entered
(B) were thought first to enter
(C) were thought at first to enter
(D) are thought of as first entering
(E) were thought to first enter
I googled this question, and people say that because "believe" is present tense, "are thought" is correct.
What about "disappeard" ? It is the past tense.
I picked e to match tense with "disappeard."
Why dose the part " are thought" have to match with "believe" in terms of tense?
The Bering land bridge already disappeared, so isn't it better to pick past tense as the answer?
This kind of tense problem is so confusing to me...