Definition: 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.
Input: Question: Organomagnesium compounds are commonly referred to as: 
 Options:  <0> Lipshutz <1> Birch. <2> Grignard. <3> Noyori <4> Blanc.
Output:
chemistry