I am with D.

Because, D does appropreate comparision for produces.

Iam confused between B and D.

But since it has to be "Which produces" instead of "Which produce"....I go with B.

B does the appropriate comparison according to me.

Please post the OA.

Thanks everybody,the real confusion was between B&D
OA is B

B is correct

its not the magnetic resonance which is producing the heat efficiently, its actually the cooking ranges which rely on magnetic resonance producing heat.

A) comparison error eff. of those(cooking ranges) relying on magnetic resonance is compared with natural gas
c)which modifies M/R , even if it is true verb produce doesn't agree with M/R
d) same in C
E)wrongly modifying M/R

what is wrong with D

Option D says

"which produce heat more efficiently than natural gas does "

which refers to "magnetic resonance", hence says that magnetic resonance produce heat more efficiently which is wrong.

IMO B....reason becoz...
ACD --- Natural gas shouldnt be compare..
IN D ...which modifies the previous noun resonence...that doesnt make sense
so i ll go with B

Hey Guys,
i think that Option B is correct, but i did not find any satisfactory reason above. Here is my explanation.


Let's look at the last words of sentence: natural gas does.

What is Natural gas ? :-- Cooking range or fuel ??

200% its a fuel. So here the comparison is
Heat generating capacity of FUELS, So you can not use Cooking RANGE on one SIDE.

so comparison here is Heat producing capacity of MAGNETIC RESONANCE and NATURAL GAS.

there is also a COMMA, indicating the non-essential modifier.

Option A and E are out because of -NON-SENSE.

Option C and D are out, because of S-V agreement, we need which produceS, not produce.

Hence B is the answer.