Answer is B.
According to the equation of motion
s = vt + 1/2 at2
Where s is distance covered, v is velocity, a is acceleration and t is time taken.
So, by putting all the values, we get
s = (20)(5) + 1/2 (3)(5)2
s = 100 + 1/2 (3)(25)
s = 100 + 1/2 75
s = 100 + 37.5
s = 137.5 meters