Which HNSW build parameter most directly increases recall at the cost of longer index build time?

1. A lists
2. ✓ B m and ef_construction (correct answer)
3. C nprobe
4. D maintenance_work_mem

Shortcut: m controls graph connectivity and ef_construction the candidate list size during build. Raising both improves recall and build time. lists and nprobe belong to IVFFlat.