Detailed Instructions: 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'.
Problem:Question: The alkali halides, MX:
Options: <1> They are solids that melt below 100C. <2> They form crystals of intense colors. <3> They can be obtained by reaction of the M2CO3 carbonates with the aqueous solutions of the HX hydrogen halides. <4> None of them can be found in nature. <5> They are liquid at room temperature.
Solution:
3