tidal pull of the moon's gravity evaporation of water from soil in the valley warming by solar energy re-radiated from the ground cooling effect of ice crystals in the air over the mountain
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: An air mass in a valley travels up a mountainside. What causes the movement of this air?
Possibilities:
- tidal pull of the moon's gravity
- evaporation of water from soil in the valley
- warming by solar energy re-radiated from the ground
- cooling effect of ice crystals in the air over the mountain

warming by solar energy re-radiated from the ground