A GIS administrator receives reports from users about a map service that is slow to...

For map services that are infrequently updated and contain numerous detailed features with complex symbology, configuring the service to use cached tiles is the most effective way to improve drawing performance. Cached map services pre-render map images at various scales and store them, allowing for faster display to users. This approach is particularly beneficial when the data does not change frequently, as it reduces the server's processing load during user interactions.​

Eliminating scale-dependent rendering (Option B) may lead to performance degradation, as it could result in rendering all features at all scales, increasing the amount of data processed and displayed unnecessarily.​

Switching to dedicated instances (Option C) can improve performance in some scenarios, but it also increases resource usage on the server. Given that the service is infrequently updated and the primary concern is drawing performance, caching is the more efficient and scalable solution.​

Reference Source: ArcGIS Enterprise documentation on optimizing map services for performance.​