Context: The passage below describes an experiment. Read the passage and then follow the instructions below.

Mary applied a thin layer of wax to the underside of her snowboard and rode the board straight down a hill. Then, she removed the wax and rode the snowboard straight down the hill again. She repeated the rides four more times, alternating whether she rode with a thin layer of wax on the board or not. Her friend Harry timed each ride. Mary and Harry calculated the average time it took to slide straight down the hill on the snowboard with wax compared to the average time on the snowboard without wax.
Figure: snowboarding down a hill.
Identify the question that Mary and Harry's experiment can best answer.
A. Does Mary's snowboard slide down a hill in less time when it has a thin layer of wax or a thick layer of wax?
B. Does Mary's snowboard slide down a hill in less time when it has a layer of wax or when it does not have a layer of wax?
From the given choices, choose the correct answer and respond with the letter of that choice.

B