The slope of log-magnitude asymptote changes by - 40 dB/ decade at a frequency ω1. This means that

a pole or zero at origin is present

a pair of complex conjugate poles is present

either a double pole or a pair of complex conjugate poles is present

The slope of log-magnitude asymptote changes by - 40 dB/ decade at a f

1.	The slope of log-magnitude asymptote changes by - 40 dB/ decade at a frequency ω1. This means that
A.	a double pole is present
B.	a pair of complex conjugate poles is present
C.	either a double pole or a pair of complex conjugate poles is present
D.	a pole or zero at origin is present
Answer» D. a pole or zero at origin is present