Explanation:

- Auxin:

- Auxins focus on cell elongation and growth, but they do not directly influence fruit ripening.

- Ethylene:

- The correct answer is ethylene. As a plant hormone, it is crucial for initiating and regulating the ripening of fruits, causing changes in texture, color, and taste.

- Gibberellins:

- These are primarily involved in promoting growth and development processes like seed germination, not directly in ripening fruits.

- None of the Above:

- This is incorrect, as ethylene is a valid answer related to fruit ripening.