Which authentication concept combines multiple authentication methods for security?

• A. Two-Factor Authentication (2FA)
• B. Multi-Factor Authentication (MFA)
• C. Knowledge-based authentication
• D. Digital certificate

Answer: (B)

Using more than one authentication factor to verify a user’s identity is the idea here. Multi-Factor Authentication means you require two or more independent credentials to sign in, drawing from categories like something you know (password), something you have (a hardware token or smartphone authenticator), and something you are (biometrics). This combination of different methods strengthens security because compromising one factor alone isn’t enough to gain access. Two-Factor Authentication is a specific instance of MFA that uses exactly two factors, but the broader concept—combining multiple methods to verify identity—is captured by MFA. The other options rely on a single factor (knowledge-based authentication is just knowledge, and a digital certificate is a cryptographic credential) and don’t inherently describe combining multiple authentication methods.