You are in mid-latitudes in winter. you experience heavy snow followed by a dramatic drop in temperature as a cold front passes, but for almost 24 hours the weather is clear. then, high clouds appear in the west, thicken to stratus clouds and you receive a light new snowfall (aka snow flurries) but the temperature remains cold.
you have just seen the passage of:

a) a second cold front
d) a warm front
c) an occluded front
d) none of these

C

Explanation:

Cold fronts move faster than warm fronts, they can catch up to and overtake their related warm front. When they do, an occluded front is formed.

 Occluded fronts are signs of mature storm systems (i.e., those about to dissipate).

The type of occlusion that is the most common normally occurs in North America is called a cold-front occlusion and it occurs when the cold front forces itself under the warm front.

the first plants to make the transition

explanation: