A digitally signed e-mail message:

A digitally signed e-mail message:
A . Validates the recipient
B . Validates the sender
C . Is encrypted
D . Is virus-free

Answer: B

Explanation:

By digitally signing a message, you apply your unique digital mark to the message. The digital signature includes your certificate and public key. This information proves to the recipient that you signed the contents of the message and not an imposter, and that the contents have not been altered in transit.

Reference: http://office.microsoft.com/en-us/outlook-help/secure-messages-with-a-digital-signature-HP001230539.aspx