Sixty-five million years ago, according to some scienti

[leonnong]

Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, which, causing plant and animal extinctions, marks the end of the geologic era known as the Cretaceous Period.
(A) which, causing plant and animal extinctions,
marks
(B) which caused the plant and animal extinctions
and marks
(C) and causing plant and animal extinctions that
mark
(D) an event that caused plant and animal
extinctions, which marks
(E) an event that caused the plant and animal
extinctions that mark

OA is E
my question is why D is wrong?
in D, "which marks" cannot modify "an event"? OG explanation is "which marks" should refer extinctions, but i think "which" refer to "an event" also make sense. please help
thanks in advance

[ntr1989512]

please help!!!

[jnelson0612]

Please see this thread, which discussed all the answer choices in great detail: sixty-five-million-years-ago-according-to-some-scientists-t2140.html