He was in a . . . . . . . . what to do and what not to do.

The correct answer is D. confusion.

The other options are not correct because:

• A. startle is a sudden feeling of fear or surprise.
• B. fix is to repair or mend something.
• C. trouble is a difficult or unpleasant situation.

The sentence “He was in a confusion what to do and what not to do” means that he was not sure what to do or what not to do. He was confused.