Final answer:
A Password is typically used as an authorization tool that verifies a user's identity by matching it against a stored value.
Step-by-step explanation:
Among the options provided, a Password is normally used as an authorization tool. When a user attempts to access a system, they are often required to provide a password that is matched against a stored value to verify their identity. A password is a secret word or string of characters that is used for user authentication to prove identity or access approval to gain access to a resource which ought to be kept secret from those not allowed access.
Other options, such as Access Control Lists (ACL), are more about specifying which users or system processes are granted access to objects, as well as what operations are allowed on given objects. A token is usually a physical device or software-based security key used in two-factor authentication. A username, on its own, is not used for authorization but for identification, as it specifies what user account is being accessed.