The sky becomes clear. Rain or snow begins to fall. Cold air is pushed to high altitudes. Warm air is pushed to ground level.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: What most likely happens when a cold air mass comes into contact with a warm, moist air mass?
Possibilities:
- The sky becomes clear.
- Rain or snow begins to fall.
- Cold air is pushed to high altitudes.
- Warm air is pushed to ground level.

Rain or snow begins to fall.