Past Perfect or Simple past? and why?

snorkeler wrote:His studies of ice-polished rocks in his Alpine
homeland, far outside the range of present-day
glaciers, led Louis Agassiz in 1837 to propose the
concept of an age in which great ice sheets had
existed in now currently temperate areas


(A) in which great ice sheets had existed in now
currently temperate areas
(B) in which great ice sheets existed in what are
now temperate areas
(C) when great ice sheets existed where there were
areas now temperate
(D) when great ice sheets had existed in current
temperate areas
(E) when great ice sheets existed in areas now that
are temperate

Simple Past vs Past Perfect.

We use simple past tense to state about something happened in past. (only 1 action in past).

Eg: I saw Rupert yesterday.

We use Past Perfect tense when we have 2 actions that happened in past and we use HAD to refer to action-1 that happened before another past action-2.

Eg: 1) My parents knew that I had done my homework.

2) The teacher THOUGHT that Lois HAD CHEATED on the exam.

Note:

a) In order to use PAST PERFECT, the sentence must also contain either a verb in the simple past tense or a time marker that occurred in the past but later than the past perfect action.

b) When the order of the events is clear then we need not to use past perfect tense.

Eg: Hampa LOCKED the door BEFORE she LEFT for work.


Now, coming to the SC question.

Read all the options vertically.

Both WHEN and IN WHICH can refer to AGE.

Now, we need to choose between EXISTED and HAD EXISTED.

From the above discussion we can see that there is no simple past or a time marker so we can't use HAD here.

A) in which great ice sheets had existed in now currently temperate areas.

HAD EXISTED is wrong. Also note that NOW CURRENTLY is redundant.

B) Correct.

C) when great ice sheets existed where there were areas now temperate.

WHERE refers to? No referent.

were...now --> wrong!

D) HAD EXISTED is wrong.

E) when great ice sheets existed in areas now that are temperate

Usage of NOW is wrong.

Sorry for my silly question...just wondering which is correct then.

•I had never seen such a beautiful beach before I went to Kauai.
•I never saw such a beautiful beach before I went to Kauai.

b) When the order of the events is clear then we need not to use past perfect tense.

Eg: Hampa LOCKED the door BEFORE she LEFT for work.