Answer:
(b) about the same as
Explanation:
Over the the water surface the potential evaporation is same as the actual evaporation. Evaporation is nothing but vaporization which takes place on the surface of liquid as it changes into gases phase. It is a process in which the liquid phases changes into gases phases on the water surface.
from above discussion it is clear that the potential evaporation is same as actual evaporation.
so option (b) will be the correct option