Which scheme needs special hardware to get data coming from I/O devices?

Explanation

DMA (Direct Memory Access) is a technique that allows data transfer between an input/output (I/O) device and memory without involving the central processing unit (CPU) as much. This improves overall system performance because the CPU can continue processing other instructions while the data transfer is happening. DMA requires a special hardware component called a DMA controller (DMAC) to manage the data transfer process. So, option (a) is correct. In conclusion, DMA is the scheme that requires special hardware to get data coming from I/O devices. It uses a DMA controller to manage data transfer directly between memory and I/O devices, reducing CPU involvement.