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: Controls the passage of substances to the central nervous system: 
 Options:  <0> Meninges. <1> Choroid plexus. <2> Hemato-encephalic barrier. <3> White substance <4> Schwann cells and oligodendrocytes.
[EX A]: biology

[EX Q]: Question: The cells of the stomach that are responsible for the secretion of hydrochloric acid are: 
 Options:  <0> The main cells. <1> The G cells <2> The parietal cells. <3> The enterocytes. <4> The mucosites of surface.
[EX A]: nursery

[EX Q]: Question: Which of the following heterocycles is considered a bioisosterer of the catecholic system ?: 
 Options:  <0> Pyridine <1> Indole. <2> Tetrazol <3> Thiophene <4> Benzimidazole
[EX A]:
pharmacology