ANS:C - a variable acceleration

The given answer is correct as velocity increases by an equal amount by an equal interval of time.

That means if the current velocity is 10m/s then after 5sec it will be 15m/s and after the next 5sec, it will be 20m/s and so on. As the velocity is changing with time so acceleration is variable. If the velocity of a body increases by equal amounts in equal intervals of time, then the body is said to be moving with uniform acceleration.

This is because acceleration is defined as the rate of change of velocity with time. If the velocity is changing by equal amounts in equal intervals of time, then the acceleration is constant, and the body is said to be moving with uniform acceleration.

Suppose velocity is increasing in such way that at t=1 distance is 2m and t=2 distance is 4m and similarly, t=3 distance is 6m then velocity V1=2m/s and V2=4m/s and V3 = 6m.

Now for Acceleration =change in velocity/change in time.
a1 = 2-0/1-0 = 2m^2/s.
a2 = 4-2/2-1 = 2m^2/s
a3 = 6-4/3-1 = 2m^2/s