What is the result of setting a lower `FILLFACTOR` (e.g., 70% instead of 100%) on an index?

1. A It enables a specialized background compression routine that automatically removes all duplicate or redundant entries from the index structure.
2. B It leaves intentional empty space within each B-Tree page, allowing future inserts and updates to be performed without causing immediate Page Splits.
3. C It significantly improves the database's initial read performance by ensuring that every page on the physical disk is packed to its absolute maximum capacity.
4. D It acts as a preventive measure against database deadlocks by ensuring that the internal row-level locks are spread across a larger number of physical storage blocks.