Which choice is an example of an idiom?

A. I knew I would never see another sunset this beautiful in a million years
B. When I looked out the window I saw it was raining cats and dogs.
C. The wind howled and screeched looking for a way to get inside
D. The clouds were a fluffy blanket that sheltered us from the midday heat

1 answer

B. When I looked out the window I saw it was raining cats and dogs.

This choice is an example of an idiom, as "raining cats and dogs" refers to heavy rain and does not literally mean that cats and dogs are falling from the sky.