An online store wants to protect user credentials and credit card information so that customers can store their credit card information and use their card for multiple separate transactions. Which of the following database designs provides the BEST security for the online store?
A. Use encryption for the credential fields and hash the credit card field
B. Encrypt the username and hash the password
C. Hash the credential fields and use encryption for the credit card field
D. Hash both the credential fields and the credit card field