A. 12.5 m/s.
The average speed is defined as the relationship between the displacement made by a body and the total time it took to perform it.
The formula that will allow you to calculate the average speed is:
v = d/t, where d is the traveled distance and t the time it took to travel the distance.
We hace to convert 4 minutes to second:
(60 s/1 min)*(4 min) = 240 s
So, the average speed is:
v = 3000 m/240 s
v = 12.5 m/s