If a system has an open loop transfer function1-s / 1+s, then the gain of the system at frequency of 1 rad/s will be

If a system has an open loop transfer function1-s / 1+s, then the gain

1.	If a system has an open loop transfer function1-s / 1+s, then the gain of the system at frequency of 1 rad/s will be
A.	1
B.	1/2
C.	Zero
D.	-1
Answer» E.