What specifically enables an 'Index-Only Scan' (Covering Index) to be faster than a standard Index Scan?

1. A It leverages specialized NVMe SSD storage protocols to bypass the standard operating system filesystem and perform direct hardware-level reads.
2. B It completely skips reading the main table (Heap) pages because the required columns are already stored within the index structure itself.
3. C It automatically converts the B-Tree index into a high-speed in-memory Hash Map to ensure constant-time O(1) performance for every query.
4. D It utilizes secondary CPU cores to parallelize the index traversal, effectively doubling the query throughput for read-only analytical workloads.