During an audit of an enterprise that is dedicated to e-commerce, the IS manager states that digital signatures are used when receiving communications from customers. To substantiate this, an IS auditor must prove that which of the following is used? 
A、A biometric, digitalized and encrypted parameter with the customer's public key 
B、A hash of the data that is transmitted and encrypted with the customer's private key 
C、A hash of the data that is transmitted and encrypted with the customer's public key 
D、The customer's scanned signature encrypted with the customer's public key