Hi vivekvijayan,

Most SCs are built on 2-4 grammar rules, and you usually don't need to know every rule involved to get the correct answer. If you find that you're unsure of how a particular grammar rule "works", then you should look at other rules that might be easier for you to deal with.

1) Command Verbs: In this SC, we have the "command"/subjunctive verb "mandate" which needs to be followed by the infinitive of whatever verb comes next. In this case, the verb needs to be "consider." Eliminate B and C.

2) Ambiguous Pronouns: The pronoun "it" can only refer back to the word "cloning", which does not making sense (how can 'cloning' be a part of researchers' professional responsibility?). Eliminate A.

3) Possessive Pronouns: Between answers D and E, the first difference that you should notice is in the phrases "THE field of development" and "THEIR field of development." The wording in D is unclear - what exactly is "THE" field of development. Researchers would likely have THEIR particular field of development though. Eliminate D.

Final Answer: E

GMAT assassins aren't born, they're made,
Rich