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: The set of means and systems that facilitate the contact of the infectious agent with the recipient subject corresponds to: 
 Options:  <0> Source of infection. <1> Habitat. <2> Transmission mechanism. <3> Biotope <4> Reservoir.
[EX A]: nursery

[EX Q]: Question: In what type of hearing loss is the phenomenon of recruitment or recruitment characteristic? 
 Options:  <0> Transmission hearing loss. <1> Mixed hearing loss. <2> Central hearing loss. <3> Retrocochlear hearing loss. <4> Cochlear hearing loss.
[EX A]: medicine

[EX Q]: Question: What is onychomycosis ?: 
 Options:  <0> An infection of the oral mucosa and gums of infants produced by Candida albicans. <1> A brain abscess in immunosuppressed caused by Aspergillus spp. <2> An infection of the nails by fungi dermatophytes. <3> A serious variety of acne in which fungal species also participate. <4> A lung infection caused by Pneumocystis jirovecii.
[EX A]:
pharmacology