Synonym of WAFT

The correct answer is B. Float.

To waft is to move gently through the air or water, especially without any apparent effort. It can also mean to spread or scatter something in the air or water in this way.

Climb is to move upwards, especially by using the hands and feet.

Sink is to move downwards, especially under the influence of gravity.

Drown is to die from being submerged in water or other liquid.

In the context of the question, waft is most similar to float. Both waft and float refer to movement through a fluid, but waft does not necessarily imply movement upwards, while float does.