Which of the following best provides e-mail message authenticity and confidentiality?

A.
Signing the message using the sender’s public key and encrypting the message using the
receiver’s private key

B.
Signing the message using the sender’s private key and encrypting the message using the
receiver’s public key

C.
Signing the message using the receiver’s private key and encrypting the message using the
sender’s public key

D.
Signing the message using the receiver’s public key and encrypting the message with the
sender’s private key