The circuit in Figure 9-8 is defective; data is not appearing on the output lines. A check with the scope shows data pulses on the serial data line and multiplex control lines, S0–S2; no parity error is indicated. A further check with a logic probe indicates that Vcc and ground appear to be present. What might be wrong with the circuit?

• A. The demultiplexer may be bad.
• B. The parity checker is defective.
• C. The parity generator may be bad.
• D. The parity checker is defective, or the parity generator may be bad.