Answer:
Answer (b)
Explanation:
Acceleration is the rate of change of velocity in time, therefore constant acceleration will be changing velocity in direct proportion to time and will have a linear plot on a velocity/time chart. This eliminates answer (d) which has an increasing acceleration in time
answer (a) has a negative slope so the acceleration would be considered negative
answer (c) has zero slope so acceleration is zero and velocity is constant.
answer (b) has the required positive slope and acceleration