In the control system shown in the figure below, a reference signal $r(t)=t^2$ is applied at time $t=0$. The control system employs a $PID$ controller $C(s)=K_p+K_1/s+K_Ds$ and the plant has a transfer function $P(s)=3/s.$ If $K_p=10,K_1=1 and K_D=2$, the steady state value of $e$ is
- $0$
- $2/3$
- $1$
- $\infty$