In a programmed input/output(PIO) __________

A. The cpu uses polling to watch the control bit constantly, looping to see if a device is ready

B. The cpu writes one data byte to the data register and sets a bit in control register to show that a byte is available
C. The cpu receives an interrupt when the device is ready for the next byte
D. The cpu runs a user written code and does accordingly

Occurrence: 0, System Administrator 2026