TASK 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.
PROBLEM: Question: In which of the drugs with antiviral activity does the purine base called guanine appear? 
 Options:  <0> Lamivudine <1> Zidovudine <2> Ribavirin <3> Acyclovir <4> Didanosine

SOLUTION: pharmacology

PROBLEM: Question: What kind of drug is clozapine? 
 Options:  <0> An anxiolytic <1> An antidepressant <2> An antipsychotic <3> A benzodiazepine <4> A hypnotic

SOLUTION: psychology

PROBLEM: Question: Determines the isotype change of the immunoglobulin heavy chain: 
 Options:  <0> The receptor of cell B. <1> The CD40 molecule and the cytokines. <2> IgM or IgD of the lymphocyte membrane. <3> Age. <4> The location of the lymphocyte within the germinal center.

SOLUTION:
biology