hi aspirant 2011. i feel C is the best answer here. please consider the following example.

Five fledgling sea eagles left their nests in western Scotland this summer, bringing to 34 the number of ..............

now bringing is modifying the entire clause

in this construct ... the sentence from merging the .........them apart is acting like a modifier for nuclear fusion ...

hence actually its like this

1st part of sentence
nuclear fusion................and hydrogen bombs, as nuclear reactors do.... ( not we are comparing nuclear fusion with nuclear reactors.)

2nd part- the modifier.

merging the .... rather than... splitting.....( x rather than y)

hence C is correct.

E- means the fusion reaction is powering and merging the nuclei... besides its too awkward a construct.

Great response, Force!

A few other problems with E:

-Because it follows a list of items separated by commas it's actually pretty unclear what the subject of "and merges" is - at best it's a comma splice that separates subject from verb, and at worst it's hard to determine the subject. You'd really need to have "and THAT merges" to make it parallel to "force that powers" and to reintroduce the subject for clarity.

-The modifier "unlike atomic reactors" has a similar problem. What is that modifying? "Merging", like Force said, modifies the entire introductory clause so it's clear. "Unlike" should be much closer to its subject, and as I mentioned above it's not even clear what the proper subject is.

-It may not be the proper decision point, but piling on...the pronoun "them" in E is even further from its antecedent (nuclei?) and separated by one more plural noun "reactors", so there's a little lack of clarity even with the pronoun. I don't know that I'd eliminate E solely on that basis, but if I were between two choices and that was the only difference I saw, I'd be leery of the pronoun placement in E.

thanks Brian. i really appreciate all your help on E.

thanks Brian for your good explanation

I see E as a comparison error. "Unlike" sets up a comparison. The way this sentence is written, it compares atomic reactors to nuclear fusion, which is incorrect.