Final answer:
When a Member is not signed into IPPS-A, they must use two-factor authentication to verify their identity. IPPS-A uses this enhanced security feature to protect sensitive military personnel data. a) Two-factor authentication is correct option.
Step-by-step explanation:
If a Member is not signed into IPPS-A, authentication through two-factor authentication is required. Integrated Personnel and Pay System-Army (IPPS-A) is a system used by the U.S. Army to manage human resources and payroll for its personnel.
Two-factor authentication, often abbreviated as 2FA, is a security process in which users provide two different authentication factors to verify themselves. This is in contrast to single-factor authentication, such as a password alone, which is less secure.
Other options like biometric verification, social media login, or email confirmation could also be used for authentication processes, but in the context of IPPS-A, typically two-factor authentication is the required method when a member is not signed in.
This typically involves entering a password and then providing a second form of identification, such as a temporary code sent to a mobile device. It helps to ensure that only authorized individuals are able to access the system.