The ICalendarDuplexCallback interface is defined as the CallbackContract property in the Service Contract. In which class should you use this line of code?
A.	Client
B.	You should never use this
C.	Both
D.	Service
Answer:D
The ICalendarDuplexCallback interface is defined as the CallbackContract property in the Service Contract. In which class should you use this line of code?
A.	Client B.	You should never use this C.	Both D.	Service