Answer:
1.5 km/s²
Explanation:
Given that:
a car starts from rest; it means the initial velocity (u) = 0 km/hr = 0 m/s
after time (t) = 20 seconds
the final velocity = 108 km/hr = 30 m/s
The acceleration (a) of the car can be determined by using the formula:



a = 1.5 km/s²
If one of the variables is changed, that tells nothing about what happens to the other one, or IF anything happens, or when, or how long it lasts. Because they are UN-RELATED. You just said so yourself.
None of the choices says this.