Given the graph of velocity versus time.
For line A, The velocity is constant throughout the time. The value of instantaneous at t=2.5 s is 4 m/s.
For line B, the value of the instantaneous velocity at t=2.5 is also 4 m/s.
Thus the value of the instantaneous velocity of both A and B at t=2.5 s is the same.
Thus the correct answer is A=B.