What does the phrase 'in vain' imply?

The phrase 'in vain' implies doing something without success or result. It is often used to express efforts or actions that yield no positive outcome, indicating that despite attempts, the desired result was not achieved. For example, if someone says they searched for their lost keys all day 'in vain,' it means they did not find the keys despite their efforts.

The other options suggest meanings that do not align with the established definition of the phrase. A indicates a successful outcome, which directly contradicts the meaning of 'in vain.' B suggests an action of emphasis, which does not relate to the notion of success or failure. C refers to a natural accompaniment, which also fails to represent the idea of achieving or not achieving a goal.