You are developing a Windows application by using Microsoft .NET Framework 4.

You plan to design a diagnostic logging strategy that will be used in a production environment.

You need to ensure that the strategy meets the following requirements:
Enables or disables diagnostic messages by using an application configuration option. Changes the level of detail in the diagnostic messages without recompiling the application.

Which class should you use?

A.
Trace

B.
Debug

C.
Contract

D.
EventLog