In terms of ξ and ωn the settling time (5% criterion) of a second order system for a step input, is equal to

In terms of ξ and ωn the settling time (5% criterion) of a second or

1.	In terms of ξ and ωn the settling time (5% criterion) of a second order system for a step input, is equal to
A.	[A].
B.	[B].
C.	[C].
D.	[D].
Answer» D. [D].