When a Car Is Weighed,it Is Driven Slowly on a Horizontal

When a car is weighed,it is driven slowly on a horizontal floor over a scale that records a reading as the front wheels go over the scale,and then records a second reading as the rear wheels go over the scale.The weight of the car is equal to

A) the reading of the scale when it is under the front wheels.
B) the reading of the scale when it is under the rear wheels.
C) the average of the two readings.
D) the sum of the two readings .
E) the difference of the two readings.