A system with zero initial conditions has the closed loop transfer function T(s) = (s2 + 4)/[(s + 1)(s + 4)]. At which frequency, will the system output be zero?

A system with zero initial conditions has the closed loop transfer fun

1.	A system with zero initial conditions has the closed loop transfer function T(s) = (s2 + 4)/[(s + 1)(s + 4)]. At which frequency, will the system output be zero?
A.	0.5 rad/sec
B.	1 rad/sec
C.	2 rad/sec
D.	4 rad/sec
Answer» D. 4 rad/sec