Answer:
D
Step-by-step explanation:
Compounds 1 and 3 are lonic.Because ionic compounds are composed of oppositely charged ions that are attracted to one another,
they require more energy to melt than covalent bonds. just usign he process of elimination you get rid of A and B becuase covalant compound contaIN same negatively charged particles that contain requrie less energy to melt and since two and four have low melting point its d