Which method is best suited for the separation of a mixture of acetone and water?

The correct option is D

Distillation

The mixture of acetone and water is separated using distillation. These liquids have different boiling points. Also, these boiling points are far apart enough which is greater than ${25}^{o}C$.

So they form vapours at different temperatures and then these vapours can be condensed separately to obtain pure liquids.

If the difference in boiling points is less than ${25}^{o}C$ , we would have to use fractional distillation.