Answer:
B. To undo his wish to bring his son back to life.
Explanation:
The Monkey's Paw by W. W. Jacobs is a short story that tells of how a family acquired a 'magical' monkey's paw from India that can make their three wishes come true. This story deals with the themes of death, faith, supernatural belief, and the issue of an Oriental artifact.
Mr. White had acquired the monkey's paw from a friend of his who told them about the special spell it was put on by a fakir in India. An with this paw, they had their two wishes granted (first was to get two hundred pounds and the second was to wish their son would come back alive), though at the cost of their son's life. The third wish was still left when they heard a scraping sound coming from the front door. It was their dead son at which the old man got frantic about wishing his final wish. And just in time before the door was opened, he made his final wish which stopped all the commotion at the door and the street was quiet. So, his final wish must have been to wish that he had not wished for his son's return from the dead and to undo the second wish.
Thus, the correct answer is option B.