GMAT Sentence Correction (SC) | Re: Numerous vegetarians believe that there are, doubtlessly,

If we keep aside the modifier 'without a doubt/undeniably...' which modifies the subject...we get

Vegetarians believe that there __ a wealth of good reasons.....

here 'a wealth' is represented i.e what is believed y vegetarians... and 'a wealth' is singular, so 'is' is applicable.

Hence,.. E is the only options using 'is' with correct subject 'vegetarians'.

Hope its clear

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