Explanation/Reference:
B: When the map tile server receives a map image tile request, it first checks to see if the requested tile is already cached. If the tile is cached, the cached tile is returned to the client. If the tile is not cached, the map tile server fetches the tile into the cache and returns it to the client. Tiles can be fetched either directly from the MapViewer map rendering engine or from an external Web map services provider.
C: The map tile server is a map image caching engine that caches and serves pregenerated, fixed-size map image tiles. It is implemented as a Java servlet that is part of the MapViewer server. The map tile server accepts requests that ask for map image tiles specified by tile zoom level and tile location (mesh code), and it sends the requested tiles back to clients.
Note: The map tile server (map image caching engine) automatically fetches and caches map image tiles rendered by Oracle MapViewer or other Web-enabled map providers. It also serves cached map image tiles to the clients, which are Web applications developed using the Oracle Maps client API. The clients can then automatically stitch multiple map image tiles into a seamless large map. Because the map image tiles are pregenerated and cached, the application users will experience fast map viewing performance.
References: https://docs.oracle.com/cd/E12839_01/web.1111/e10145/vis_omaps.htm#JIMPV9780