After going through various suggestions by GMAT experts at Magoosh and Manhattan, I could arrive at the following conclusion:

The positive....comparative...superlative forms of certain adjectives of quantity are as follows:

set 1. many...more...most
set 2. much...more....most
set 3. great...greater...greatest

While set 1 (many...more...most) is used for countable nouns, set 2 (much...more....most) and set 3 (great...greater...greatest) are used for uncountable nouns.

Now there could be 2 types of uncountable nouns
type a. Quantity word / numbers themselves (e.g. price, volume, weight, probability etc.) are uncountable.
type b. Other uncountable nouns (honesty, poverty, etc as you mentioned)

The set 2 (much...more....most) is used for type b (other uncountable nouns) uncountable nouns.
The set 3 ( great...greater...greatest) is used for type a (Quantity word / numbers) uncountable nouns.

Therefore we see that "more" can be used for (i) countable nouns and (ii) uncountable nouns that are not quantity words/ numbers.
"Greater" can be used for (iii) uncountable nouns that are quantity words/ numbers.

Thank you daagh

So in option 'A' apart from the usage of 'more' there's nothing else wrong, right?


Thanks
Saurabh

SS18, if you're being really strict and literal with the meaning here, (A) and (C) are both just a little bit illogical.

In (C), the clearest issue is that the verb tense is a little bit off. "... the more coffee the doctors drank, the more they would have a likelihood to have coronary disease." One problem is "would have" -- the phrase conditional, which doesn't make much sense here. We're looking at facts of a study: "the more x occurred, the more y occurred". Since these are facts, it wouldn't make sense to say: "the more x occurred, the more y would have occurred." There's simply no need to make the second part of the phrase conditional.

In (A), it doesn't make much sense to say "the more they had a likelihood." It makes sense to talk about the degree to which something is likely to occur: "a higher likelihood" or "a greater likelihood." But this is subtly different: (A) is saying "the more they had a likelihood" -- which seems to express "likelihood" as a binary thing, that you either have or you don't -- so now (A) seems to say that the more the physicians drank, the higher the odds of having a likelihood. And that doesn't make much sense. (C) suffers from the same problem, too.

I hope this helps!

GMATNinja, can you elaborate a little more on option A. Also, if we replace "they" with "doctors" in "more they had a likelihood of coronary disease", can we say the sentence is saying that more doctors had a likelihood that is the number of doctors ?