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 hydrides has the highest normal boiling point? 
 Options:  <1> SiH4. <2> CH4 <3> HCl. <4> PH3. <5> HF
