Correct Answer: DImplementing multi-factor authentication (MFA) is the best recommendation to prevent unauthorized access to cloud-based applications and data. MFA adds an additional layer of security by requiring users to provide more than one form of verification before accessing a system or application. This could include a combination of something the user knows (like a password), something the user has (like a smartphone for a verification code), or something the user is (like a biometric factor). By requiring multiple forms of verification, MFA significantly reduces the likelihood that an unauthorized individual could gain access, even if they obtain a user's primary credentials.