What happened?

You work as an enterprise administrator at Domain.com. The Domain.com network consists of
a single Active Directory domain named Domain.com. All servers on the Domain.com network run Windows Server 2008.
Domain.com has a federation relationship with a company named Courseware Publishers that was implemented with the use of Federation Services with Windows Server 2003 R2. You have also made use of the federation service with named accounts to better the security. However, due to an upgrade to AD FS, you notice that the named account used to run the service is removed and replaced with the Network Service account. You need to find out what has happened.
What happened?

A.
It could be that Network Service is the default service account used in an AD FS installation or upgrade.

B.
It could be that Courseware Publishers contains a policy that states that the federation services should be run with the Network Service account.

C.
It could be that you are not able to use named service accounts to run the AD FS service.

D.
It could be that Microsoft favors using Network Service account to run federation services.

Explanation:
During an installation the named service account is automatically replaced by the Network service account. You need to reset the service account for all Active Directory Federation Services.
Incorrect Answers:
B: The policies will affect the servers on Courseware Publishers’ network not Domain.com.
C: All services make use of a named service account to run.