Correct Answer: Anything from the past that isn't significant or important anymore.

Solution : The correct answer is the second option.

The idiom "water under the bridge" conveys that something from the past, typically a past issue or disagreement, is no longer significant. It suggests that the matter has been resolved or forgiven, and there's no need to dwell on it.

The meanings of the other options are as follows:

To be very sick: This option does not accurately capture the meaning of the idiom. The idiom "Water under the bridge" is not associated with illness.

A paranormal sense that allows you to communicate with the dead: This option does not relate to the idiom's actual meaning. "Water under the bridge" is not associated with paranormal abilities.

Someone else who takes the blame: This option does not capture the essence of the idiom, which is about letting go of past issues rather than shifting blame to someone else.

Therefore, the correct answer is: Anything from the past that isn't significant or important anymore.