HELP!!!!!!THXXXXXXXXXX

When take into account the response time of the driver, the answer is incorrect.

The total distance s for a car with initial speed u to stop is,
s = s1 + s2
where s1 is the distance travelled by the car during the driver's response
and s2 is the distance travelled by the car after the brake is applied.

s1 = ut', t' is the response time of the driver
s2 = u^2/2a, where a is the decceleration of the car

hence, s = ut' + u^2/2a
s is thus not directly proportional to u^2

As v^2 - u^2 = 2as => s= v^2 - u^2 / 2a
As v=0,
s= - u^2 / 2a
Since a is negative (deceleration), then S is directly proportional to u^2
Hence the stopping distance of a car (s) is directly proportional to the sqare of the initial velocity (u).
Correct.