What are the two leading design solutions recommended by Oracle that you would use for...

C: OBIEE Caching and Cache Seeding

Cache is a component that improves performance by transparently storing data such that future requests for the same criteria can be served much faster. Like other application cache is not virtual memory in OBIEE. In OBIEE cache will be stored as files on the Hard Disk of the OBIEE Server in the form of files. By Default caching is enabled in the OBIEE server configuration.

For time-consuming Dashboard Pages, we can use the concept of cache seeding in OBIEE, this can be configured as a scheduled job that will ensure that the data is cached and readily available as and when the user runs the dashboard.