Which device serves to enhance multimedia capabilities in a computer?

The graphics card is the correct choice because it is specifically designed to manage and accelerate the rendering of images, animations, and video for output to a display. This enhancement is critical for multimedia applications such as gaming, video editing, and graphic design, as it takes the processing load off the CPU and provides improved performance for visual tasks.

In contrast, RAM is used primarily for short-term data storage and retrieval, making it essential for overall system performance but not specifically for enhancing multimedia capabilities. The network card facilitates communication over a network and does not contribute to the multimedia processing directly. The CPU, while critical for overall performance and capable of handling multimedia tasks, does not focus on graphics processing to the extent that a dedicated graphics card does. Therefore, the graphics card stands out as the dedicated component that enhances multimedia abilities in a computer.