According to the Cisco documentation12, single sign-on (SSO) in PCCE can be implemented in one of these three modes:

SSO - Enable all agents and supervisors in the deployment for SSO. This mode requires the use of SAML assertions to exchange authentication and authorization details between an identity provider (IdP) and an identity service (IdS)1.

SAML - Security Assertion Markup Language (SAML) is an XML-based standard that allows the IdP to issue SAML assertions, which are packages of security information transferred from the IdP to the service provider for user authentication1. SAML is the underlying technology that enables SSO in PCCE2.

Hybrid - Enable agents and supervisors selectively in the deployment for SSO. Hybrid mode allows you to phase in the migration of agents from a non-SSO deployment to an SSO deployment and enable SSO for local PGs. Hybrid mode is useful if you have third-party applications that don’t support SSO, and some agents and supervisors must be SSO-disabled to sign in to those applications1.

Option A is incorrect because Non-SSO is the opposite of SSO, and it means continuing to use existing Active Directory-based and local authentication, without SSO1. Option C is incorrect because ldS is a typo for IdS, which is not a mode but a component of SSO. Option D is incorrect because ldP is a typo for IdP, which is also not a mode but a component of SSO.

References:

1: Single Sign-On - Cisco3

2: Cisco Packaged Contact Center Enterprise Features Guide Release 11.6 (1) - Single Sign-On [Cisco Packaged Contact Center Enterprise] - Cisco

SSO - Enable all agents and supervisors in the deployment for SSO.

Hybrid - Enable agents and supervisors selectively in the deployment for SSO. ...

Non-SSO - Continue to use existing Active Directory-based and local authentication, without SSO.

https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cust_contact/contact_center/pcce/pcce_12_6_1/maintenance/guide/pcce_b_features-guide-1261/pcce_b_features-guide-1261_chapter_01110.html