You need to ensure that all users in the Contoso domain…

You install the Service Manager Self-Service Portal on a server named CONTOSOSSP1.
Users report that they receive access denied messages when they try to connect to the portal.
You must grant users the minimum required permissions.
You need to ensure that all users in the Contoso domain can access the Service Manager Self- Service Portal.
What should you do?

A.
In Active Directory, create a new group named PortalUsers.
Add the PortalUsers group to the Contoso\\Domain Users group, and then add the group to the local users group on CONTOSOSSP1.

B.
Using the account that you used to install the Self-Service portal, grant the Contoso\\Domain Users group Read permissions to the portal.

C.
In Service Manager, create a new user role named PortalUsers.
Grant the PortalUsers role rights to all catalog items, and then add the Contoso\\Domain Users Active Directory Domain Services group to the PortalUsers role.

D.
Using the account that you used to install the Self-Serviceportal, grant the Contoso\\Domain Users group Contribute permissions to the portal.

Explanation:
Need to Check
Using the account that you used to install the Self-Serviceportal, grant the Contoso\\Domain Users group Contribute permissions to the portal.
Self Service Portal Users only need READ Access.
http://www.certifychat.com/70-414-a/272-install-service-manager-self-service-portal-server-named-contosossp1.html?highlight=ensure+users+Contoso+domain
+access+Service+Manager+Self-+Service+Portal.