Which of the following choices meets the minimum requirement needed to create specialized waveforms that are used in digital control and sequencing circuits?

• A. basic gates, a clock oscillator, and a repetitive waveform generator
• B. basic gates, a clock oscillator, and a Johnson shift counter
• C. basic gates, a clock oscillator, and a DeMorgan pulse generator
• D. basic gates, a clock oscillator, a repetitive waveform generator, and a Johnson shift counter