What gets its characteristics from the area it forms over?

The weather in a location often depends on what type of air mass is over it. Another key factor revolves around whether or not the spot is beneath a front, the meeting place of two air masses. The characteristics of the air masses and their interactions can determine whether the weather is constant over an area, or whether there are rapid changes in air temperature, wind, precipitation and even thunderstorms.

The answer i think is d