Correct Option: C

The given circuit

Given

Vi = u(t) then Vi(s) =	1
	S

Applying KVL to the input loop, we get

Vit = i(t) R + L	di(t)	+	1	∫i(t) dt
	dt		C

Taking laplace transform both side, we get

1	=		R + LS +	1		I(S)
S				CS

or

1	=	RCS + LCS2 + 1
S		S

The characteristic equation RCS + LCS² + 1 = 0

or S2 +	R	S +	1	= 0
	L		LC

2ξωn =	R
	L

and

ω2n =	L
	LC

Now,

ξ =	R
	2ωn

=	R
	L2	√	1
			LC

Putting the given values of R, L and C, we get
ξ = 1
Since, ξ = 1
Thus, the transient current response of the circuit is critically damped. Hence alternative (D) is the correct choice.