After more than four decades of research and development

[RonPurewal]

Can any one of the experts explain the problem that D and E cause when the modifier is split into two clauses by the ", and"? Thanks in advance.

Not a modifier. In those two choices, the grammatical structure is
(complete sentence) + , and + (another complete sentence)

This is a perfectly respectable grammatical structure. The problems lie elsewhere.

[RonPurewal]

Among other things:

• D has blatant non-parallelism

• E is redundant (could + capability)

[RonPurewal]

Also, these things don't really make sense in parallel ("thing A and thing B"), since one describes characteristics the engine itself while the other describes what's currently happening to it. The structure of the correct answer—in which the characteristic is presented as a modifier—is more sensible.

This is a rather subtle point; it definitely won't be the ONLY issue with an incorrect answer choice. (Note the much more easily grasped errors mentioned immediately above.) But, if you understand it, it's another weapon in your arsenal.

[RichaChampion]

I got this question in my Exam Pack 1, which is a Free Exam Pack not paid one.
Apart from Redundancy that most forums have discussed is there anything else wrong in this answer choice.

[RonPurewal]

EVERYTHING from GMAT Prep that includes the word "Pack" is a paid source.

Exam Pack 1 is a paid item that costs US$50.
http://www.mba.com/us/store/store-catal ... ack-1.aspx

so, we'll have to lock this thread.