The correct answer is: B. ignore the past.
The phrase “let bygones be bygones” means to forget about the past and move on. It is often used to advise someone to stop dwelling on negative experiences and focus on the present.
Option A, resist the past, is incorrect because it suggests that the past should be fought against. This is not the case, as the past is already over and cannot be changed.
Option C, recollect the past, is incorrect because it suggests that the past should be remembered. While it is important to learn from the past, it is not healthy to dwell on it.
Option D, revive the past, is incorrect because it suggests that the past should be brought back to life. This is not possible, as the past is gone and cannot be changed.
In conclusion, the correct answer is: B. ignore the past.