The rate of evaporation from the surface of a lake would be increased by

The rate of evaporation on the surface of a lake would be increased by the sunlught.

The more intense the sunlight, the bigger the temperature, the more the water gets warmer, thus evaporates at a higher rate. On the other hand, if the sunlight is weaker, the temperatures are lower, the water cools off, thus the evaporation will be at a smaller rate.