An occluded front is usually caused by a().
A、cold front becoming stationary
B、warm front becoming stationary
C、cold front overtaking a warm front
D、warm front dissipating
A、cold front becoming stationary
B、warm front becoming stationary
C、cold front overtaking a warm front
D、warm front dissipating
A、low pressure area B、high pressure area C、area of calm air D、cold front overtaking a warm front