Explanation:

- Equanimity refers to mental calmness, composure, and evenness of temper, especially in difficult situations.

- Option 1: calmness of mind or temper

- This accurately captures the essence of equanimity.

- It's the state of being peaceful and maintaining a steady mind.

- Correct Answer

- Option 2: corresponding

- This means having similarity or a close connection with something.

- Not relevant as a synonym for equanimity.

- Option 3: conservatory

- Refers to a greenhouse or a school for art and music.

- Unrelated to the meaning of equanimity.

- Option 4: shorten

- Means to reduce in length or duration.

- Not aligned with the meaning of equanimity.