Select the most appropriate meaning of the given idiom.

Up in arms

to be ready to fight with

The correct answer is to be ready to fight with. The idiom "up in arms" means to be very angry or to be ready to fight. It is often used to describe a group of people who are protesting or who are opposed to something. For example, you might say "The people were up in arms about the new tax laws."

The other options are incorrect. "In close vicinity" is the meaning of the idiom "in the near vicinity." "Active in work" is the meaning of the idiom "to be hard at work." "Being discussed" is not an idiom.