Which is most often a result of a warm air mass moving over a cooler air mass

When a warm air mass moves into an area of cooler air, the boundary between the air masses is called a warm front. The warmer, less-dense air slides up over the cooler, denser air in a wide, gentle slope. As the warm air cools, its relative humidity increases, and the water vapor condenses into clouds.

Explanation:

the answer is c. according to past decisions, free speech is not unlimited.