Which of the following provides two-factor authentication?

Two-factor authentication (2FA) is a security mechanism that requires two different forms of identity verification before access is granted to a system or application. The correct choice, which is the bank card and PIN, exemplifies this concept effectively.

In this scenario, the bank card serves as a physical possession that the user must have (something you have), while the PIN is a piece of knowledge that the user must know (something you know). This combination of a physical object and a knowledge-based authentication method meets the criteria for two-factor authentication, as it reduces the likelihood of unauthorized access since both components are necessary for authentication.

Other options, while they may offer some level of security, do not fit the 2FA model as strictly. The combination of a username and password relies solely on knowledge (something you know) and does not include a second factor. The fingerprint and iris scan rely on biometrics (something you are) but do not incorporate another form of verification. Lastly, a key and proximity badge can involve the possession factor but may not necessarily combine it with a knowledge component like a PIN or password, which is integral to true two-factor authentication.