The correct option is B 6 m/s2
As we know that the acceleration of the particle is given by
a=dvdt and also, v=dxdt
Given, x=3t2−6t+4
So, v=dxdt=d(3t2−6t+4)dt
⇒ v=6t−6
also, a=dvdt=d(6t−6)dt=6
Thus, the acceleration of the particle is constant i.e 6 m/s2