After Restoring an Amazon RDS Snapshot from 3 Days Ago

Multiple Choice

After restoring an Amazon RDS snapshot from 3 days ago, a company's Development team cannot connect to the restored RDS DB instance. What is the likely cause of this problem?

A) The restored DB instance does not have Enhanced Monitoring enabled
B) The production DB instance is using a custom parameter group
C) The restored DB instance is using the default security group
D) The production DB instance is using a custom option group