○　正解です。

When we feel sick we use the idiom 'under the weather'.
For example : I feel under the weather. I think I'm catching a cold.

'On cloud nine' means to feel very, very happy.
For example : When my daughter passed the entrance exams, I was on cloud nine.

''Shaken up' means to be very shocked and surprised.
For example : After the car crash, I was shaken up.