Which solution would have the greatest drop in freezing point (freezing point=0 degrees C)

Solutions:
A:MgCl2
B:NH4
C:NaCl
D:Na3P

Idont know. if you want an answer you need to give us some context dude.

What are the options? physical property can be color, smell, opacity, viscosity, density, infra red spectrum, melting and boiling points, attraction and repulson to magnets, etc.

The ratio is 3: 2. i.e. c.