Explanation: Display system memory, especially in radar applications, is primarily used for a process called **target integration** or **scan correlation**. By storing data from multiple successive radar sweeps, the system can compare these returns. Real targets, such as other vessels, consistently appear in roughly the same location over several scans. In contrast, fluctuating interference like sea return (reflections from waves) or rain clutter is transient and inconsistent, appearing randomly or briefly. The memory allows the system to build a more stable and coherent display. It reinforces persistent target echoes while effectively filtering out or suppressing the erratic, non-coherent clutter signals, making true targets much clearer and easier to distinguish from background noise. Option B is incorrect because radar inherently detects and displays both stationary and moving targets without memory being its *primary* purpose for this. Option C describes a power backup or last-state recall function, not the main role of display memory in target processing. Option D, storing target bearings, is part of the general data processing of a detected target, but the primary purpose of memory for *display improvement* is to eliminate clutter.