When the interviewer asked a question like this. The correct way to reply to this question professionally is to start explaining what is MFA. Like the demo answer below

Multi-factor authentication (MFA) plays a pivotal role in bolstering access controls and mitigating the risk of unauthorized access. Its primary function is to add an extra layer of verification beyond the traditional username and password. By requiring users to provide at least two different forms of identification, such as a password and a temporary code sent to a registered device, MFA significantly enhances security.

Moreover, MFA aligns with the principle of ‘something you know, something you have, and something you are,’ making it a robust method for verifying the identity of users. This not only reduces the risk of unauthorized access due to compromised credentials but also provides an additional layer of security against various attack vectors, including phishing and brute-force attacks