We describe a protocol of input device communication below:
i) Each device has a distinct address.
ii) The BUS controller scans each device in a sequence of increasing address value to determine if the entity wishes to communicate
iii) The device ready to communicate leaves its data in the I/O register
iv) The data is picked up and the controller moves to the step a
Identify the form of communication best describes the I/O mode amongst the following.

A. Programmed mode of data transfer

B. DMA

C. Interrupt mode

D. Polling

Answer: Option D