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: Polarography is an analytical technique that refers to: 
 Options:  <0> The absorption of electromagnetic radiation. <1> The emission of electromagnetic radiation. <2> The voltametry with mercury electrode. <3> The use of palladium as a reference electrode. <4> To the potential of asymmetry.
Output:
chemistry