What item should an architect advise the identity team at UC to investigate first?

customer service representatives at Universal containers (UC) are complaining that whenever they click on links to case records and are asked to login with SAML SSO, they are being redirected to the salesforce home tab and not the specific case record .

What item should an architect advise the identity team at UC to investigate first?
A . My domain is configured and active within salesforce.
B . The salesforce SSO settings are using http post
C . The identity provider is correctly preserving the Relay state
D . The users have the correct Federation ID within salesforce.

Answer: C