A. 4 plates
B. 6 plates
C. 2 plates
D. 8 plates
I have been asked this question in a national level competition.
This key question is from Cathode Ray Tube topic in portion Oscilloscopes of Electrical Measurements
The best I can explain: Cathode ray tube consists of two sets of plates that are parallel in nature. They are referred to as horizontal and vertical deflection plates. One of the plates is set to ground potential.