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: It has a recessive inheritance linked to the X chromosome the: 
 Options:  <0> Acatalasemia <1> Hemophilia A. <2> Rett syndrome. <3> Cystic fibrosis, <4> Hypophosphatemia
[EX A]: 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 acetylation of the stories affects the transcription: 
 Options:  <0> Blocking the incorporation of other components of the transcription machinery. <1> Preventing the remodeling of chromatin. <2> Facilitating the action of helicases. <3> Decreasing the sensitivity of nuclear receptors. <4> Reducing the affinity of histones for DNA.
[EX A]:
pharmacology