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: Aflatoxin B1 is a natural product that owes its toxicity to a product of its metabolism, very reactive, of the nature of:
Options: <0> 1,2-Diol. <1> Quinonymine <2> Epoxide <3> , -unsaturated carbonyl. <4> Radical hydroperoxide.
[EX A]: pharmacology

[EX Q]: Question: In a cohort study, the number of new cases of disease per person per unit of time is:
Options: <0> The annual incidence. <1> The cumulative incidence or probability. <2> The prevalence rate <3> The density or incidence rate. <4> The relative risk of developing the disease.
[EX A]: medicine

[EX Q]: Question: Friedel-Crafts alkylation reactions lead to products that:
Options: <0> They facilitate diazotization reactions. <1> They facilitate the reactions of formation of ethers. <2> Activate the aromatic ring against other substitutions. <3> They deactivate the aromatic ring against other substitutions. <4> None of the above.
[EX A]:
chemistry