Definition: In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.
Input: Question: Which of the following detectors is used in Infrared Spectroscopy? 
 Options:  <1> Photomultiplier tube. <2> Flame ionization detector. <3> Potentiostat. <4> Proportional counter <5> Deuterated triglycine sulfate crystal.
