Assume you have saved a product in the Catalog. Will your last changes be taken into account for rule-based related products?
A. Only if you go to the "Catalog/Rule-based Product Relations" page, and hit "Reindex All" button.
B. Only if you clear the cache.
C. Yes: It will be done automatically by an observer on the catalog_product_save_after event.
D. Yes: Rule-based related products are calculated on-the-fly.