In terms of ξ and ωn the settling time of a second order systems for 2% criterion and step input is equal to

In terms of ξ and ωn the settling time of a second order systems for

1.	In terms of ξ and ωn the settling time of a second order systems for 2% criterion and step input is equal to
A.	[A].
B.	[B].
C.	[C].
D.	[D].
Answer» E.