The correct choice is (c) 14cm/sec^2
Explanation: Let f be the acceleration of the particle in time t seconds. Then,
f = dv/dt = d(3t^2 – 4t + 5)/dt
= 6t – 4 ……….(1)
Therefore, the acceleration of the particle at the end of 3 seconds,
= [f]t = 3 = (6*3 – 4) cm/sec^2
= 14cm/sec^2