Normally associated with airplane construction, wind-tunnel testing ha

OFFICIAL EXPLANATION

I truly have no idea where to start. My test just went off the rails.

What was my test? To see whether you remembered the idiom
NOT SO MUCH X AS Y.
That idiom anchors this question, here.

On that topic thread I explained the idiom in this post, here.

The good news is that you all can handle mechanical parallelism..

I am not convinced that I see an understanding of what this sentence means.
On the other hand, elimination is quick and easy, so I can't tell whether you took the short route (smart move) but still understand the sentence.

• Meaning
NOT SO MUCH X AS Y (a preposition can be added, but those words are the basic idiom)

When we say that something is not so much one thing as something else, we mean that the something is "more" the second thing.

Typically wind tunnel testing is used on airplanes as they are being built.
Wind tunnel testing tells builders whether the airplane is aerodynamic—whether its shape reduces the drag from air that moves past the airplane as the plane flies through the air.
Planes that are not aerodynamic do not fly. They must be built properly.

Wind tunnel testing is also done on cars.
Cars don't fly. Wind tunnel testing is done in part to test whether the shape of the cars is aerodynamic.
But the bigger reason wind tunnel testing is done on cars is that testers want to make the cars more power efficient.
The cars can drive even if they are not very aerodynamic. But wind tunnel testing helps to determine ways to make the cars use less power while driving on a road.

Cars are subject to wind tunnel testing not so much to ensure that they can cut through the air with little resistance in order to work properly as to determine ways to make cars use less power as they drive on roads.

And yes, the grammatical splits help a lot.

• Split #1: Parallelism - to maintain parallelism, to calculate must be paired with to determine
Wind tunnel testing is used on cars [not so much] to calculate . . . as to determine ways . . . .

In options A, C, and D, the X and Y elements are not parallel.

To determine is correct because the phrase is parallel with to calculate
Option (A) incorrectly uses determining
Option (C) incorrectly uses it has determined
Option (D) incorrectly uses in the determination of

Eliminate A, C, and D

• Split #2: the correct idiom is required TO, not required for the ___ING of

Aside from idiom, you could use concision to decide between B and E.
(B) required for the moving of
(D) required to move

Option D is clearer and more concise than B.

Idiom?
This one you just have to remember.
When require is a verb or past participle (verbED) it is followed by TO.
-- He is required to do community service.
-- Visas, required to enter the country, are hard to get.

If you see that X is required for Y, ask, is X required in order to do Y?
If so, then the sentence should say X is required to do why.

Require overwhelmingly takes TO or THAT and nothing else.
Option B uses "required for the moving of . . . " Not idiomatic.
Eliminate B.

The answer is E

COMMENTS

LalitaSiri and RichiSharma , welcome to SC Butler. TheNighking -- your avatar is awesome.

Everyone handled parallelism and the awkward wording in B very well.
See whether you can articulate what the sentence means. (Two of you can. I can see it.)
Kudos to all.


** The idiom, by the way, is NOT SO MUCH X AS Y.
Variations on that idiom are
NOT SO MUCH BY X AS BY Y
NOT SO MUCH TO X AS TO Y

I'm just making sure that people understand the general idiom.
Prepositions can be added to that idiom, as is the case in this question.