The correct option is Data de-identification.

Data de-identification is the category that includes obfuscation because it covers techniques that remove or alter personal identifiers to reduce the chance of re identification. This category includes masking, pseudonymization, anonymization and other obfuscation methods that aim to preserve data utility while protecting privacy.

Data de-identification focuses on breaking the link between data and the original identity so that records cannot be tied back to an individual without additional information. Obfuscation is a natural fit under this goal because it transforms or hides identifying elements rather than relying solely on cryptographic secrecy.

Hashing is incorrect because hashing is a one way cryptographic transformation used for integrity checks and creating fixed length fingerprints. It is not primarily an obfuscation technique for preserving analytic utility or reversible pseudonymization.

Encryption is incorrect because encryption protects confidentiality by converting data into ciphertext that is reversible with a key. That property makes encryption different from obfuscation methods used in de identification which are intended to mask or remove identifiers while allowing safe use of the data.

Key management is incorrect because it is an operational practice that supports cryptographic techniques rather than a category of data protection that includes obfuscation. Key management is about generating storing and protecting keys and it does not itself change data to remove identifiers.

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