When a maritime tropical air mass collides with a continental polar air mass, the maritime tropical air mass is generally less dense and warmer, so it will rise above the colder, denser continental polar air mass. This upward movement can lead to the formation of clouds and precipitation, often resulting in thunderstorms, especially when there is significant moisture present in the maritime tropical air mass.
Given the choices, the correct response would be:
The maritime tropical air mass would rise above the continental polar air mass, and thunderstorms would form.