Answer:
correct answer is Stationary
Step-by-step explanation:
solution
the correct answer is Stationary because when 2 mass of air is pushing each other opposite direction but there is no power to move other mass of air than their stationary front is form as a cold front or the warm front stop moving
and the wind blowing parallel to the front instead of perpendicular that can help it stay in a place
so correct answer is Stationary