E4E01 - Amateur Extra Class

E4E01 : What problem can occur when using an automatic notch filter (ANF) to remove interfering carriers while receiving CW signals?
A Removal of the CW signal as well as the interfering carrier
B Any nearby signal passing through the DSP system will overwhelm the desired signal
C Excessive ringing
D All these choices are correct
Correct Answer: Removal of the CW signal as well as the interfering carrier