What mechanism should an architect put in place to enable a trusted connection between the login services and salesforce?

Universal containers (UC) is setting up Delegated Authentication to allow employees to log inusing their corporate credentials. UC’s security team is concerned about the risk of exposing the corporate login service on the Internet and has asked that a reliable trust mechanism be put in place between the login service and salesforce .

What mechanism should an architect put in place to enable a trusted connection between the login services and salesforce?
A . Include client ID and client secret in the login header callout.
B. Set up a proxy server for the login service in the DMZ.
C. Require the use ofSalesforce security Tokens on password.
D. Enforce mutual Authentication between systems using SSL.

Answer: C