Act 1 of The Tragedy of Julius Caesar

At the beginning of Act I, Scene iii, of The Tragedy of Julius Caesar, why is
Casca upset as he describes the thunderstorm?

A. He is afraid that he will be hit by lightning and killed.
B. He is worried that the thunderstorm is really the sound of fighting.
C. He is afraid that the gods are angry and something bad will happen.
D. He is afraid that Caesar is angry and will blame him for the weather.