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.
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Question: 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.

Answer: chemistry


Question: 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

Answer: pharmacology


Question: Question: Which of these vitamins are isoprenoid compounds? 
 Options:  <0> Vitamins A, B2, C and D. <1> Vitamins A, B2 and Folic acid. <2> Vitamins A, K and biotin. <3> Vitamins D, E and C. <4> Vitamins A, D, E and K.

Answer:
chemistry