The man already has the paper ball above the trash can so it can't be A, the man isn't throwing the ball to the side of the trash can so it can't be B, the guy is not far away from the trash can so it can't be C, the right answer is D.
Williams show that the wheelbarrow is an essential part of life on a farm through the phrase: "so much depends upon" it leads the readers to infere the importance of the wheelbarrow.