For each situation, specify whether you expect the gain at frequency f to increase, decrease, or not change much at all.
a) A zero is moved closer to frequency f on the z-plane.
b) A pole is moved closer to frequency f on the z-plane.
c) A zero already near frequency f on the z-plane is replaced with a double zero.
d) A pole already near frequency f on the z-plane is replaced with a double pole.
e) A pole currently near frequency f on the z-plane is moved to the origin.
f) A pole currently near frequency f on the z-plane is outside the unit circle.