A Website Keeps a Record of User Actions Using a Globally

A website keeps a record of user actions using a globally unique identifier (GIUD) retrieved from Amazon Aurora in place of the user name within the audit record. Security protocols state that the GUID content must not leave the company's Amazon VPC. As the web traffic has increased, the number of web servers and Aurora read replicas has also increased to keep up with the user record reads for the GUID. What should be done to reduce the number of read replicas required while improving performance?

A) Keep the user name and GUID in memory on the web server instance so that the association can be remade on demand. Remove the record after 30 minutes.
B) Deploy a Amazon ElastiCache for Redis server into the infrastructure and store the user name and GUID there. Retrieve GUID from ElastiCache when required.
C) Encrypt the GUID using Base64 and store it in the user's session cookie. Decrypt the GUID when an audit record is needed.
D) Change the GUID to an MD5 hash of the user name, so that the value can be calculated on demand without referring to the database.