The incompatibilities in speed between the various devices and the CPU make I/O synchronization difficult, especially if there are multiple devices attempting to do I/O at the same time. To handle these problems data is usually stored

In a buffer

Explanation:

We can define a buffer as a temporary holding area for data between the various devices and the CPU make I/O synchronization especially if there are multiple devices attempting to do I/O at the same time.

Items stored at the buffer helps to reduce the The incompatibilities in speed between the various devices and the CPU.

the answer will be d