For cross-tenant B2B collaboration between contoso.com and fabrikam.com, which of fabrikam.com's identity providers support cross-tenant access?

For cross-tenant B2B collaboration, Azure AD B2B supports direct federation with other Azure AD tenants. This means users from fabrikam.com's Microsoft Entra ID can directly access resources in contoso.com. While Azure AD B2B also supports federation with other identity providers like Google (GCP) and Microsoft accounts (MSA), these are typically used for inviting individual guest users who do not have an Azure AD account, not for direct cross-tenant collaboration between two organizations where both have Azure AD. Therefore, only Microsoft Entra ID provides the native, direct cross-tenant access for B2B collaboration in this scenario.