You need to resolve this exception

You create a .NET Remoting object named AdminService, which is hosted in Internet Information Services (IIS). The object uses an HttpChannel and a BinaryFormatter. AdminService is in an assembly named AdminService.dll. The URL for AdminService is http://LocalHost/AdminService/AS.rem.

You write a test console application named Tester.exe to test the AdminService interface. Tester.exe includes the following code segment:

public class Tester {
public static void Main(string[] Args) {
AdminService service = new AdminService();
// Code to exercise the service object.
}
}

You write a configuration file for Tester.exe. The configuration file is named Tester.exe.config and
includes the following code segment:
You run Tester.exe. The application immediately throws a System.NullReferenceException. The exception includes the following message: “Object reference not set to an instance of an object.” You need to resolve this exception.

What should you do?

A.
To the application element of the Tester.exe.config file, add the following code segment:
<channels>
<channel ref=”http”>
<clientProviders>
<formatter ref=”binary”/>
</clientProviders>
</channel>
</channels>

B.
Replace the use of the AdminService constructor in Tester.exe with the following code segment:
AdminService service =
(AdminService)Activator.CreateInstance(
typeof(AdminService));

C.
At the beginning of the Main method in Tester.exe, add the following line of code:
RemotingConfiguration.Configure(“Tester.exe.config”);

D.
Rename the configuration file from Tester.exe.config to Tester.config.