Which solution is more secure than the traditional use of a username and password and encompasses at least two of the methods of authentication?

RADIUS/LDAP authentication are protocols and directory services for authentication, but they don't inherently define multiple factors of authentication; they typically facilitate authentication based on a single factor unless specifically configured for MFA integration.

Single-sign-on (SSO) is about convenience, allowing users to authenticate once and gain access to multiple services without re-entering credentials; it does not inherently provide multifactor authentication.

Kerberos is a network authentication protocol that provides strong authentication using secret-key cryptography, but it primarily relies on 'something you know' (password) to obtain tickets and does not inherently encompass multiple factors.

Multifactor authentication (MFA) strengthens security by combining multiple authentication factors. These factors typically include 'something you know' (like a password), 'something you have' (like a token or mobile device), and 'something you are' (like a fingerprint or facial scan), making it significantly harder for unauthorized users to gain access even if one factor is compromised.