You have a secured Windows Communication Foundation (WCF) service.
You need to track unsuccessful attempts to access the service. What should you do?

A.
Set the authorizationManagerType attribute of the serviceAuthorization behavior to Message.

B.
Set the includeExceptionDetailslnFaults attribute of the serviceDebug behavior to true.

C.
Set the Mode attribute of the security configuration element to Message.

D.
Set the messageAuthenticationAuditLevel attribute of the serviceSecurityAudit behavior to Failure.

Explanation:
<ServiceSecurityAudit>
Specifies settings that enable auditing of security events during service operations.

The AuditLevel is an enumeration with the following members:

Failure : Only failed security-related events are recorded.
None : No events are recorded.
Success : Only successful security-related events are recorded.
SuccessOrFailure : Both failed and successful security-related events are recorded.

<ServiceSecurityAudit>
(http://msdn.microsoft.com/en-us/library/ms731694.aspx)