The mitochondrial enzyme involved in the metabolism of clopidorgel and proton pump inhibitors is (AI 2012)
Clopidogrel and proton pump inhibitors are metabolized mainly by CYP2C19 and by CYP3A4.
Due to this reason there is potential of interaction between these two drugs but none of these enzymes were given in the options. We have no idea what the examiner want a student to learn. Whether student should know the clinically important things or they should go for the most rarest of things.
Anyways, some of these drugs are also metabolized by CYP2C9. On searching a lot, we came to know that this enzyme (CYP2C9) was previously known as CYP2CI0. (Ref: http://www.genecards.org/cgi-bin/carddisp. pl? gene = CYP2C9).
So the answer among the given options should be CYP2CI0. But again we will suggest to remember about 2C19 which is clinically more relevant.