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.	1/ξωn
B.	2/ξωn
C.	3/ξωn
D.	4/ξωn
Answer» D. 4/ξωn