Answer: a.CCl4 aka carbon tetrachloride
Step-by-step explanation:
ionic compounds and polar molecules can be dissolved in water which is a polar solvent.
choice d (KF) is a salt (an ionic compound) and can be dissolved in water /(K+ and F- ions would be formed in water).
choice c (NH3 or ammonia) is a very polar molecule and thus can be dissolved in water(Hydrogen bonding).
choice b (CH3Cl) is slightly polar because the atoms surrounding the central carbon atom are different(3 H atoms and 1 chlorine atom) and can be dissolved in water(Dipole-dipole interaction).
choice a is nonpolar and cannot be dissolved in water.