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 term that includes the changes of the endometrium during pregnancy is: 
 Options:  <0> Hatching. <1> Apposition. <2> Accession. <3> Invasion. <4> Decidualization.
[A]: biology


[Q]: Question: The main virulence factor of Streptococcus pneumoniae is one (one): 
 Options:  <0> Fímbria. <1> Capsule. <2> Scourge <3> Endotoxin <4> Adhesin
[A]: biology


[Q]: Question: In the aromatic electrophilic substitution with a monosubstituted benzene ring, the halogens are: 
 Options:  <0> Ortho / for leaders but activating. <1> Target leaders but activating. <2> Goal / for leaders but activating. <3> Ortho / goal leaders but activating. <4> Ortho / for leaders but deactivators.
[A]:
chemistry