In the following question, there is a sentence which is divided into four parts. Choose the fragment that carries an error (if any). Ignore punctuation errors if any.
The problem with the mainstream Indian Left / is that though they are honest and committed bunch of politicians but are / unwilling to look inward, to find out what is wrong / with Marxism in theory and in practice.
is that though they are honest and committed bunch of politicians but are
The 2nd fragment has serious errors. First is that the pronoun 'they' has no proper antecedent. The antecedent seems to be the Indian Left - which is to be treated a singular. The next error is that the collective will begin with an article. Hence, 'they are an honest and committed bunch of' will be correct. The other fragments have no problems.