Which of the following hives in the Windows Registry hierarchical database is volatile in nature...

HKEY_CLASSES_ROOT (HKCR)is the Windows Registry location that storesfile-association and COM registration data, including mappings forfile extensions(e.g.,.docx) toProgIDs, and COM object identifiers such asCLSIDand interface-related identifiers likeIID. In forensic examinations, HKCR is frequently consulted to determine which application is registered to open a specific file type, to identify COM objects that may enable persistence or abuse (e.g., through COM hijacking), and to correlate suspicious registry-based execution mechanisms with installed software.

HKCR is often described asvolatile in naturebecause it is not a single standalone hive file stored independently in the same way as SAM or SYSTEM; instead, it is amerged, runtime viewcreated by the OS primarily fromHKLM\Software\Classes(machine-wide registrations) andHKCU\Software\Classes(per-user overrides). This means what you see under HKCR can vary depending on the current user context and system state, and the effective associations/registrations may change when software is installed, updated, or when per-user settings override machine defaults.

The other options represent different scopes: HKLM is system configuration, HKCU is user profile configuration, and HKCC reflects the current hardware profile—not the primary COM/file association repository.