To ensure message integrity, confidentiality and nonrepudiation between two parties, the MOST effective method would be to create a message digest by applying a cryptographic hashing algorithm against: 
A、the entire message, enciphering the message digest using the sender's private key, enciphering the message with a symmetric key and enciphering the key by using the receiver's public key. 
B、any part of the message, enciphering the message digest using the sender's private key, enciphering the message with a symmetric key and enciphering the key using the receiver's public key. 
C、the entire message, enciphering the message digest using the sender's private key, enciphering the message with a symmetric key and enciphering both the encrypted message and digest using the receiver's public key. 
D、the entire message, enciphering the message digest using the sender's private key and enciphering the message using the receiver's public key.