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.

Ex Input:
Question: The 2,4-diaminopteridine systems, such as aminopterin or methotrexate, are good antitumor agents since they reduce the biosynthesis of purines and pyrimidines by inhibiting the enzyme: 
 Options:  <0> Timidylate synthetase <1> Aromatase <2> Topoisomerase <3> Reverse transcriptase <4> Dihydrofolate reductase.

Ex Output:
pharmacology


Ex Input:
Question: Enzymatic regulation by reversible covalent modification: 
 Options:  <0> It involves the breaking of the peptide bond. <1> It requires the action of another enzyme. <2> It always involves phosphorylation reaction. <3> It never affects allosteric enzymes. <4> The enzyme never comes in two forms.

Ex Output:
biology


Ex Input:
Question: At what stage of problem-solving therapy are the principles of quantity, deferment of judgment and variety used? 
 Options:  <0> Decision making. <1> Orientation towards the problem. <2> Definition and formulation of the problem. <3> Generation of alternative solutions. <4> Implementation and verification of the solution.

Ex Output:

psychology