If phase angle of open loop transfer function becomes - 180° at frequency ω1, then gain margin is equal to

If phase angle of open loop transfer function becomes - 180° at frequ

1.	If phase angle of open loop transfer function becomes - 180° at frequency ω1, then gain margin is equal to
A.	\|G(jω1)\|
B.	[B].
C.	1 + \|G(jω1)\|
D.	[D].
Answer» C. 1 + \|G(jω1)\|