Task: Question Answering
Input (English): Question: The carcinogenic action of Benzo (a) pyrene: 
 Options:  <1> It is due to the production of oxygen free radicals. <2> It is due to its biotransformation in a dihydrodiol. <3> It is due to its biotransformation in an epoxide. <4> It increases in tissues rich in epoxide hydrolase. <5> It diminishes in tissues rich in cytochrome P450.
Output (English): 3