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: For the analysis of traces of inorganic constituents, in samples of organic nature, a preliminary treatment of the sample is needed, which normally consists of: 
 Options:  <0> Dissolve the sample in cold water. <1> Dissolve the sample in hot water. <2> Dissolve the sample between 30 and 70 ºC. <3> Heat the sample between 400 and 700 ºC. <4> Heat the sample in 0.1 M hydrochloric acid.
[A]: chemistry


[Q]: Question: The treatment of choice for Post Traumatic Stress Disorder in childhood is: 
 Options:  <0> The cognitive restructuring. <1> The exhibition, both in imagination and live. <2> No treatment has been proven more effective than the rest. <3> Planning of pleasant activities and training in social skills. <4> The relaxation technique alone has proven to be more effective than the rest.
[A]: psychology


[Q]: Question: Serum disease is a hypersensitivity: 
 Options:  <0> Mediated by IgE. <1> Against molecules of the extracellular matrix. <2> Mediated by deposition of immune complexes in certain tissues. <3> With formation of granulomas. <4> With activation of mast cells associated with blood vessels.
[A]:
biology