Single Sign-On (SSO) is primarily designed to address accountability and assurance. SSO is a mechanism that enables a user to authenticate once and gain access to multiple systems or applications without having to reauthenticate. SSO improves accountability by providing a centralized and consistent way of managing user identities and access rights across different systems or applications. SSO also improves assurance by reducing the risk of password compromise, user fatigue, and human error, as users do not have to remember or enter multiple passwords. The other options are not the primary goals of SSO, but rather secondary benefits or challenges. Option A is a description of confidentiality and integrity, which are security properties that SSO can enhance by using strong encryption and authentication methods, but they are not the main purpose of SSO. Option B is a description of availability and accountability, which are security properties that SSO can improve by simplifying the user experience and reducing the authentication overhead, but they are not the primary objectives of SSO. Option C is a description of integrity and availability, which are security properties that SSO can support by ensuring the consistency and reliability of user data and access, but they are not the main focus of SSO. References: CISSP All-in-One Exam Guide, Eighth Edition, Chapter 5, p. 281; Official (ISC)2 CISSP CBK Reference, Fifth Edition, Chapter 6, p. 355.