The idiom 'At the drop of a hat' means to do something immediately without any delay or hesitation. This phrase is often used to describe actions that are undertaken promptly and spontaneously. For instance, if someone is willing to help you at the drop of a hat, they are ready to assist you right away, without having to think about it.
When examining the given options:
Therefore, the correct answer is To do something immediately.
The politician's vague answers clearly showed he was just beating around the bush.
What does "beating around the bush" imply?
The CEO's sudden resignation threw the board into a tailspin.
What does the idiom "threw into a tailspin" mean?