Got your PM and am responding.
Although people break the "no split infinitive" rule all the time, to the point that it has become somewhat accepted in the mainstream, the GMAT is old school: it still holds to the "no split infinitive" rule. So eliminate A.
The general set-up to this sentence is an if-then set-up: If X happens, then Y will happen. Sam's right that the word "should" can be substituted for the word "If" in this context - it's an old-fashioned construction but perfectly correct. (Notice that we're not saying "Barney should eat his Wheaties" - meaning I think Barney should eat his Wheaties. That's a different connotation. When you see the set-up "Should Barney eat his Wheaties, he will be healthy," you're just seeing a classic if-then set-up.)
So, C fixes that infinitive problem we had and is the correct answer.
B is wrong because of the "are continuing." When your connotation is "if something happens" that should be in simple present, not present continuous.
D messes up the "should" thing! Now, the sentence actually is saying "I think this should be this way."
E same thing. (Not to mention: "metal prices' sharp rise continuing"? Ouch.)
Also: watch out for the old-fashioned constructions. They often sound wrong to our ears because no one speaks that way anymore. ("Shall we have tea now?") But there's nothing wrong grammatically! And this is one very common way in which they tempt us to eliminate the right answer.
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Stacey Koprince
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Manhattan GMAT
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