Which of the following is a compound sentence?
A. Predicting the weather can be very difficult and is based on a number of complicated factors.
B. Most names given to clouds describe their shapes and positions to help us identify them.
C. Lightning is caused by electrical charges, and it always occurs before the sound of thunder.
D. Water evaporates into the air from oceans, lakes, and rivers, and eventually becomes vapor and clouds.
PLEASE HELP!
