IMO - D
You are right "Here THEY can refer to stomach disorders or drugs ". But all other choices are having other issues and ambiguity is not absolute rule to cross of option. So we still can go with D.

whats wrong with A?

bubbliiiiiiii wrote:whats wrong with A?

@Pranay: "A" also has referent issue for "them" but to me "enough to have them" seems to be less preferable to "such ..that" construction in "D".

Hi Target2009,

whats wrong with option C.......... I chose C because I found "them" to be ambiguous in option D and also in option C idiom "so x as to be y" is being used

aspirant2011 wrote:Hi Target2009,

whats wrong with option C.......... I chose C because I found "them" to be ambiguous in option D and also in option C idiom "so x as to be y" is being used

SUCH...SO AS TO BE... Seems u missed Such.

yup ........thanks target2009

Here's the important thing to remember about pronoun ambiguity: it's a style issue, not a grammar issue. So, if you have to choose between two choices, both of which are grammatically correct but one of which is ambiguous, go with the non-ambiguous choice.

However, when all the choices contain the same level of ambiguity, you can completely ignore the issue. On this particular question none of the choices make it explicitly clear that "banned" refers to the suppressants, so ambiguity is a non-issue. Remember, getting rid of the pronoun without replacing it with a better reference word doesn't fix the problem (which is why (C) isn't any less ambiguous than the other choices).

There have definitely been real GMAT questions that used ambiguous pronouns; in each such case, the parent noun was clear from the context of the sentence. In most cases a previous pronoun in the sentence makes it clear to what the latter phrase is referring (in this question, the pronoun "these" sets the precedent for "they" to refer back to the suppressants).