Paul’s class investigated the effects of friction on the motion of a toy car. Using ramps with different surfaces, students determined the amount of time, in seconds (s), for the toy cars to reach the bottom of each ramp. All variables were controlled except the tested variable (independent variable). Paul's group concluded that toy cars on a sandpaper surface are fastest.

Which statement best evaluates the group's conclusion?

A) The results support the conclusion.
B)The conclusion is valid for the data recorded.
C) The results fail to support the conclusion.
D) More data need to be added to the conclusion.