Choose the most appropriate meaning of the given idiom.
At the drop of a hat

The correct answer is Immediately.

Explanation:
The idiom "at the drop of a hat" is an informal expression used to describe doing something instantly, without any hesitation, delay, or prior warning.

Origin of the idiom:
Historically, in 19th-century America, dropping a hat or sweeping a hat downward was often used as a visual signal to mark the start of a contest, race, or fight. Since participants had to react instantly the moment the hat dropped, the phrase came to mean doing something instantly or without delay.

Breakdown of the options:
• Consecutively: Refers to things following continuously in an uninterrupted sequence (e.g., one after another).
• Eventually: Means in the end or after a long time.
• Certainly: Means without a doubt or definitely.
• Immediately: Means right away or instantly, which matches the exact meaning of "at the drop of a hat".