Task: Text Categorization
Input (English): 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> Α, β-unsaturated carbonyl. <4> Radical hydroperoxide.
Output (English): pharmacology