What Is Interrupt- Driven I/O and What Is Its Major

Multiple Choice

What is interrupt- driven I/O and what is its major advantage?

A) Each individual I/O device is serviced sequentially on a regular basis by the PIC. This speeds up the I/O process.
B) An I/O device needing service sends a request to the PIC (programmable interrupt controller) , which in turn notifies the CPU of the request based on the assigned priority level of the specific I/O device. If there are no pending I/O requests the CPU does not have to spend time checking the I/O ports.
C) Each individual I/O device is checked sequentially on a regular basis to see if it needs to be serviced. This slows down the CPU operation.
D) Individual I/O devices regularly send inquiries to the CPU to see if it is available for a specific I/O operation; if the CPU is available, the I/O device then proceeds to carry out its operation.