Explanation:

- By and by is an idiom that means "in a while" or "eventually," often pointing to something that will happen in due course or after a short time.

- Option 1: Gradually - Suggests something happening slowly over time, not quite the direct meaning of "by and by."

- Option 2: By any means - Implies doing whatever necessary to achieve something, unrelated to "by and by."

- Option 3: Suddenly - Means happening quickly without notice, almost opposite to the patience implied in "by and by."

- Option 4: On the whole - Refers to considering everything together, not relevant to "by and by."

- The correct answer is Option 1: Gradually . It captures the essence of something happening over time.