Definition: In this task, you are given a question and answer options for that question. Using this information, you have to classify each text into different topics: medicine, nursery, psychology, chemistry, pharmacology, biology.
Input: Question: Allopurinol, as an inhibitor of xanthine oxidase:
Options: <0> It is suicidal, reversible. <1> It is suicidal, irreversible. <2> It is analogous to the transition state, reversible. <3> Inhibits the enzyme by proteolysis. <4> Allopurinol does not inhibit that enzyme.
Output:
chemistry