E4D03 - Amateur Extra Class

E4D03 : What creates intermodulation interference between two repeaters in close proximity?
A The output signals cause feedback in the final amplifier of one or both transmitters
B The output signals mix in the final amplifier of one or both transmitters
C The input frequencies are harmonically related
D The output frequencies are harmonically related
Correct Answer: The output signals mix in the final amplifier of one or both transmitters