The correct option is Identity based access control.

Identity based access control grants permissions to specific users or accounts and lets the owner of the resource decide who gets access. This owner driven assignment of rights matches the definition of discretionary access control because control over permissions is left to the resource owner rather than imposed by a central policy.

Rule based access control is incorrect because it enforces access through system rules or conditions such as time or network location and does not rely on the resource owner granting access at their discretion.

Mandatory access control is incorrect because it uses centrally managed labels and policies to enforce access and it prevents owners from making discretionary changes to permissions.

Role based access control is incorrect because it assigns permissions to roles that are managed by administrators and organizations and it does not provide the same owner level discretion that defines discretionary access control.

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