Which of the following must be set to enable a device to directly access memory on the system, without the CPU's intervention?

The correct answer is Direct Memory Access (DMA). This feature allows certain hardware subsystems within the computer to access the main system memory (RAM) independently of the central processing unit (CPU). By enabling direct access to memory, DMA improves the efficiency of data transfers and system performance, as the CPU is freed from the task of moving data, allowing it to focus on executing other processes.

When a device, such as a disk drive or a sound card, uses DMA, it can communicate with RAM directly. This is especially advantageous in high-speed data transfer scenarios, like streaming video or audio, where continuous data flow is necessary. Enabling DMA minimizes delays and overhead that occur when the CPU is involved in every data transfer operation.

In contrast, other options listed relate to different types of memory or caching techniques. For instance, Dynamic Random Access Memory (DRAM) and Static RAM (SRAM) are types of memory used for storing data temporarily or permanently within a system. Cache Memory refers to a smaller, faster type of volatile memory that provides high-speed access to frequently used data but does not facilitate direct access to memory by hardware devices. Therefore, it is Direct Memory Access that specifically enables devices to bypass CPU intervention for memory operations.