A dual trace oscilloscope is set to operate in the ALTernate mode. The control input of the multiplexer used in the y-circuit is fed with a signal having a frequency equal to

• A. the highest frequency that the multiplexer can operate properly
• B. twice the frequency of the time base (sweep) oscillator
• C. the frequency of the time base (sweep) oscillator
• D. half the frequency of the time base (sweep) oscillator