You are designing a Windows Presentation Foundation (WPF) application for your company by using Microsoft .NET Framework 4 and Microsoft Visual Studio 2010. The business layer of the application is implemented by using Windows Communication Foundation (WCF). You plan to support nonrepudiation and data integrity for WCF messages. You need to design the security strategy for the application. What should you do?

A.
Attach a digital signature to the WCF messages.

B.
Encrypt the WCF messages by using the Secure Sockets Layer (SSL) protocol.

C.
Encrypt the WCF messages by using the Internet Protocol Security (IPSec) protocol.

D.
Implement messagelevel security by using digital certificates as client computer credentials.