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.

[Q]: Question: The organometallic react with the nitriles giving: 
 Options:  <0> Amino acids. <1> Lactones. <2> Alcohols <3> Ketones <4> None of the above.
[A]: chemistry


[Q]: Question: The Grignard reagents attack the epoxides to give, after the appropriate hydrolysis: 
 Options:  <0> Carboxylic acids. <1> Cyclic amides. <2> Open aliphatic chains. <3> Open-chain alcohols. <4> Cyclic ethers.
[A]: pharmacology


[Q]: Question: The set of means and systems that facilitate the contact of the infectious agent with the recipient subject corresponds to: 
 Options:  <0> Source of infection. <1> Habitat. <2> Transmission mechanism. <3> Biotope <4> Reservoir.
[A]:
nursery