E4E05 - Amateur Extra Class

E4E05 : What is used to suppress radio frequency interference from a line-driven AC motor?
A A high-pass filter in series with the motors power leads
B A brute-force AC-line filter in series with the motors power leads
C A bypass capacitor in series with the motors field winding
D A bypass choke in parallel with the motors field winding
Correct Answer: A brute-force AC-line filter in series with the motors power leads