English Idioms Challenge (Multiple Choice)

What does the idiom "break a leg" mean in the following sentence? 
Before her performance, her friend told her to break a leg.

What does the idiom "miss the boat" mean in the following sentence? "He didn't apply for the scholarship on time and ended up missing the boat on a great opportunity."

To fail to take advantage of an opportunity.

What does the idiom "the ball is in your court" mean in the following sentence? "I've given you all the information you need; now the ball is in your court."

To be waiting for a response from someone else.

To be playing a game of tennis or basketball.

It is up to you to make the next decision or step.

What does the idiom "feel under the weather" mean in the following sentence? "I can't come to work today; I'm feeling a bit under the weather."

To be enjoying the outdoors in bad weather.

What does the idiom "let the cat out of the bag" mean in the following sentence? "They were planning a surprise party, but someone let the cat out of the bag."

To literally release a feline from a container.

What does the idiom "hit the nail on the head" mean in the following sentence? "You hit the nail on the head when you said the main issue is communication."

To physically strike something with a hammer.

To describe exactly what is causing a situation or problem.

What does the idiom "break a leg" mean in the following sentence? Before her performance, her friend told her to break a leg.