A. Sheila ate her lunch in the cafeteria.
Answer: One fact is that a simple sentence Is just the basics of a sentence, the bare minimum, but a compound sentence is two sentences combined with a and, but or comma.
Explanation:
Example: I like pizza. I like ice cream.= I like pizza and ice cream. I like pizza, but also ice cream.
Answer:
Going to the beach is fun, but the mountains are even better.
Explanation:
Adding that extra "but" correctly compares the two sentences in one.