Comprehensive and Detailed Explanation From Exact Extract:
The guide on RAG and search indexes indicates that if you need fine#tuned retrieval behaviour (such as filtering by product line and ranking by recency), you should build a custom retriever. The documentation states: "You can add ranking factors such as recency and popularity at the time of index creation ... Use pre#filter fields and ranking factors." Also: "When you create a search index, Data 360 automatically creates a default retriever ... you can create custom retrievers in Einstein Studio to refine search criteria." Hence to satisfy filtering by product line and recency ranking, the correct answer is B. Option A (default retriever) does not guarantee the filter/ranking customization; Option C (semantic embeddings with default metadata filters) may offer some filter capability but doesn't explicitly provide ranking by recency and fine filter by product line. Thus B is correct.