Final answer:
To resolve the access issue for SalesUser1 who is unable to connect to a shared resource after GSales group was corrected from Distribution to Security group type, SalesUser1 should sign out and sign back in to get a new security token with updated permissions.
Step-by-step explanation:
The issue here is that after GSales was changed back from a Distribution group to a Security group, the permissions associated with it do not immediately reflect in the user's login session. In this case, SalesUser1 is unable to access the shared resource because the security token that was issued at the time of login does not have the updated group membership information. The correct course of action would be:
C. Ask SalesUser1 to sign out and sign back in.
This is because when SalesUser1 logs in again, a new security token that includes the updated group memberships will be generated. This will allow the necessary access permissions to the shared resource on the PRACTICELABS domain.