Definition: In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.
Input: Question: In what type of reaction does the cytochrome P-450 of the liver typically intervene? 
 Options:  <1> Hydration. <2> Reduction. <3> Hydrolysis. <4> Esterification <5> Hydroxylation
