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: To silence messenger RNA (mRNA) siRNAs and miRNAs are usually linked to your: 
 Options:  <0> TATA box. <1> 5'-UTR. <2> 5 'cap. <3> 3'-UTR. <4> Poly (A) 3 tail.
[EX A]: biology

[EX Q]: Question: In oxidative stress it is characteristic: 
 Options:  <0> Decrease in the concentration of oxidized glutathione. <1> Increase in the concentration of reduced glutathione. <2> Decreased production of reactive oxygen species. <3> Increase in the production of reactive oxygen species. <4> None of the previous are true.
[EX A]: chemistry

[EX Q]: Question: Indicate which of the following deficits leads to a porphyria: 
 Options:  <0> Phenylalanine hydroxylase. <1> 21-hydroxylase. <2> ALA dehydratase. <3> Glucokinase. <4> Tyrosine hydroxylase.
[EX A]:
pharmacology