Despite the influx of international aid to a particularly

[miteshsholay]

Despite the influx of international aid to a particularly war-torn region of East Africa during the waning months of 2006, in early 2007, many indigenous people unable to find food left their home to travel west where other tribal groups historically experienced less difficulties producing food, water, and land.
A) their home to travel west where other tribal groups historically experienced less difficulties
B) home to travel west where other tribal groups historically experienced fewer difficulties
C) their home to travel west where other tribal groups historically experienced fewer difficulties
D) home to travel west in search of other tribal groups who historically had experienced fewer difficulties
E) home to travel west where other tribal groups historically had experienced fewer difficulties

Source:
http://www.platinumgmat.com/practice_gmat_questions/sentence_correction_questions

My concern:
I was able to eliminate A, C and D.
But I am stuck between options B and E.
I finally chose B, but the correct answer is E.
As far as I know, we don't need to use past perfect tense if we have already indicated timeline by using words such as 'Earlier', 'Previously' etc.
Why do we need to use past perfect tense such as in option E when we have already indicated the timeline by using 'historically' ?

[RonPurewal]

the most important thing to know, here, is that this problem isn't representative of the gmat. this is a fairly subtle distinction; i've never seen an official problem that requires a subtle verb-tense distinction. (when such distinctions have appeared, they have invariably been accompanied by other, much more conspicuous errors.)

"historically", in this context, means that we're talking about an observation prior to the timeframe of the sentence. furthermore, that observation clearly has an impact on the action described in the sentence (that's the reason why the people moved!).
these two conditions -- (a) prior to the timeframe of the sentence and (b) direct impact on what's described in the sentence -- are exactly the circumstances under which "had VERBed" is the correct tense.

[miteshsholay]

Thanks for the reply Ron.
I didn't completely get the point.

"historically", in this context, means that we're talking about an observation prior to the timeframe of the sentence.

This is the reason why I think we can avoid past perfect tense.
Or do you mean it should be prior to the timeframe of the events in the sentence in order to avoid past perfect?

I revisited the Perfect Tense part of SC Guide but couldn't apply here.
Would you please explain in simpler terms if possible?

[RonPurewal]

i am going to stick with what i said in my earlier post -- the distinction here is much too subtle for the gmat exam. you shouldn't worry about it; there's no possible benefit for the gmat (and a high chance of confusion).

"platinum gmat" is now a banned source on this forum, so this thread is now closed.