Kelly, a professional hacker, used her laptop to perform illegal cyber activities for monetary gain...

The scenario describes the use ofBitLockerto lock an entire disk volume with asecret key, preventing access to the contents. In digital forensics, this is a classic example ofencryption as an anti-forensics technique. Full-disk or full-volume encryption transforms readable data into ciphertext using cryptographic algorithms so that, without the correct key (password, recovery key, TPM-bound protector, etc.), the data is computationally infeasible to interpret. This directly obstructs evidence acquisition and analysis because a forensic image of the drive will largely contain encrypted blocks rather than interpretable file system structures and user data.

This differs from the other options:file carvingis a forensic recovery method (often used by investigators) that reconstructs files from unallocated space; it is not an anti-forensics method used to block access.Artifact wipingattempts to erase traces by deleting or overwriting files, logs, or free space, but it does not inherently prevent access to remaining data if wiping is incomplete.Trail obfuscationinvolves misleading or altering logs and traces to confuse investigators, whereas encryption primarilydenies content visibilityby design. Because BitLocker is explicitly a volume encryption mechanism used here to deny access, the correct anti-forensic technique isEncryption (D).