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 Q]: Question: Polarography is an analytical technique that refers to: 
 Options:  <0> The absorption of electromagnetic radiation. <1> The emission of electromagnetic radiation. <2> The voltametry with mercury electrode. <3> The use of palladium as a reference electrode. <4> To the potential of asymmetry.
[EX A]: chemistry

[EX Q]: Question: The reactivity of various carbonyl groups is determined by their relative stability. The order of reactivity towards nucleophiles is: 
 Options:  <0> Amides> Esters> Ketones> Aldehydes. <1> Aldehydes> Ketones> Esters> Amides. <2> Amides> Ketones> Aldehydes> Esters. <3> Aldehydes> Esters> Ketones> Amides. <4> Amides> Ketones> Esters> Aldehydes.
[EX A]: chemistry

[EX Q]: Question: The dye-test (Sanbin-Feldman test) is the reference method for the diagnosis of: 
 Options:  <0> Cryptosporidiosis. <1> Sarcocystosis <2> Malaria. <3> Toxoplasmosis <4> Cyclosporosis
[EX A]:
pharmacology