D:= Driving is difficult
W:= The weather is stormy
The sentence means:
W ==> D
Read as "W implies D"
Which basically just means:
Whenever we have W, we have D, too! Always. We can't have W without also having D.
In this case, we are given W (the weather is stormy). So, we must also have D! (Driving is difficult)
The answer is C.
