What does two-factor authentication typically involve?

Two-factor authentication (2FA) is a security process in which the user provides two different authentication factors to verify themselves. This typically involves something the user knows (like a password or PIN) combined with something the user has or is (such as a smart card, mobile device, or biometric data).

Option B is correct because it describes this combination effectively. When a user logs in to an account, they first enter their password (the first factor) and then are prompted for a second factor, which could be a code generated by a smart card or a biometric scan, like a fingerprint or facial recognition. This dual-layer approach provides an additional level of security, making it significantly harder for unauthorized users to gain access, as they would need both the password and the second factor.

The other options do not meet the criteria for two-factor authentication. Using just a single password (the first option) does not incorporate a second factor and therefore does not enhance security. Verifying identity through email confirmation (the third option) is also considered a single factor, as it relies solely on the possession of the email account. Requiring a phone number for login (the fourth option), while useful, does not automatically equate to two-factor authentication unless it is used in