On which device is swap space or page file reserved?

Swap space or page file is reserved on the hard disk. This area of the disk is used to extend the physical memory of a system, allowing for a larger pool of memory by using part of the hard drive as virtual memory. When the physical RAM is full, the operating system moves data that is not actively being used from the RAM to the swap space on the hard disk. This process helps prevent system slowdowns and allows more applications to run simultaneously, effectively managing memory resources.

The reason the other choices are not correct is because the motherboard does not reserve swap space; it hosts the RAM and CPU. Memory refers to the physical RAM itself, which is where active processes and data are stored but does not include the disk-based virtual memory. The CPU handles processing but does not bear any responsibility for memory allocation in the form of swap space. Thus, the hard disk is the correct answer as it provides the necessary storage for the swap space or page file.