Out of the following given choices;
a. decelerate; accelerate
b. accelerate; decelerate
c. stop; accelerate
d. decelerate; stop
The answer is B. This is because the cold front usually rotates around the warm front as cold air mass coverage in the low-pressure system. This causes the cold air mass to accelerate to catch up with the warm front. When an occluded front ( that is the boundary that separates the older cool air mass already in place from new incoming cold air mass), that the system decelerates.