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.

Example 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.
Example Output: pharmacology

Example Input: Question: The reaction between a ketone and a Grignard reagent causes, after hydrolysing the salt formed, a: 
 Options:  <0> Carboxylic ester. <1> Alcohol. <2> Ether. <3> Aldehyde. <4> Carboxylic acid.
Example Output: chemistry

Example Input: Question: The only autonomic adrenergic fibers are axons of neurons: 
 Options:  <0> Sympathetic preganglions. <1> Postganglionic sympathetics. <2> Preganglionic parasympathetic. <3> Postganglionic parasympathetic. <4> Parasympathetic ganglion.
Example Output:
pharmacology