"the monkeys paw" consider the end of the story . how does jacobs create suspense and surprise at the end with the banging and opening of the door?

Jacobs doesn’t tell readers who was at the door, leaving the story open to interpretation. Like the Whites, readers don’t know if the person banging on the door was indeed Herbert, the Whites’ dead son. Through the ending, Jacobs offers readers a choice between a rational explanation and a supernatural one. Even Mr. White isn’t sure if Herbert’s death is a mere coincidence, or if the monkey’s paw really did grant him his wish in a twisted way. When Mrs. White opens the door, she finds the road empty. Readers aren’t positive that Mr. White’s third wish made Herbert go away.

The answer is a it reinforces the difference between the natural things the speaker holds dear and the rituals of the church