Answer :
Final answer:
A DoD PKI token is appropriate for B. accessing a secured military network.
Explanation:
The DoD PKI token is a type of smart card that provides strong authentication and secure access to DoD systems and networks. It is issued to authorized personnel and contains cryptographic keys that verify the user's identity.
Logging into a social media account and making an online purchase do not require the level of security provided by a DoD PKI token. These activities can be done using standard usernames and passwords or other authentication methods.
Unlocking a personal smartphone also does not require a DoD PKI token. Personal smartphones typically use different forms of authentication, such as PINs, patterns, or fingerprints, to unlock the device.
Therefore, the correct option is B. accessing a secured military network.
