GMATGuruNY wrote:
A: making...flames spreading more quickly
Here, the usage of spreading is incorrect.
The usage of making requires the BARE INFINITIVE form of to spread, as follows:
making flames SPREAD more quickly.
Here, spread = bare infinitive (to spread with the to omitted).
Eliminate A.

Hi Mitch,
Thanks a ton for the insightful post. I knew about Bare Infinitives but was never so clear about them.
Just a small doubt regarding the SC question. I think, even if we replace the underlined part with flames SPREAD, the sentence would not convey a logical meaning.
Verb+ing modifier making refers back to the subject of the previous clause i.e. radiation. Now, radiation can make ignition much easier because it preheats the fuel, but can it (radiation) make flames spread? Little awkward meaning.
I think because of the inconsistency in meaning, another verb, cause, was necessary to introduce. Pls comment on that.
Thanks.

binit wrote:I think, even if we replace the underlined part with flames SPREAD, the sentence would not convey a logical meaning.
Verb+ing modifier making refers back to the subject of the previous clause i.e. radiation. Now, radiation can make ignition much easier because it preheats the fuel, but can it (radiation) make flames spread? Little awkward meaning.

Option A, if spreading is replaced with spread:
radiation that preheats the fuel, making flames spread more quickly.

Here, the usage of preheats implies that the fuel is heated BEFORE it has contact with the flames, with the result that the flames spread AFTER -- and because -- the fuel has been PREHEATED.
Thus, the usage of COMMA + making -- which implies that radiation is MAKING the flames spread AT THE SAME TIME as the fuel is preheated -- is inappropriate.