What is the climax of the story?

The story's climax takes place near the end when Mrs. White wishes for her son to return, and suddenly, the couple hears a knock at the door.

While many believe the ending to be where the climax happens, we need to look before the ending. I believe the climax is when the parent's find out of the death of their son. Not only is this of highest tension, the climax must also be when a character "changes." Mr. and Mrs. White change with the death of their son, therefore, the points after this would lead into the falling action and the resolution.