Answer:
B; NaF because it is a ionic compound
Explanation:
First off, just looking at A and C, you can eliminate them because they are inherently false statements:
A) NaF is not covalent; it is ionic because it is made up of a metal (Na) and a nonmetal (F)
C) CH4 is not ionic; it is covalent because it is solely made up of nonmetals (C and H)
Now, a property of ionic compounds is that when they are either molten (melted) or dissolved, they melt in water. Covalent compounds are NOT good conductors of electricity.
Thus, B (NaF because it is a ionic compound) is the answer.
