Which 2 measures should data architect recommend to avoid any performance issues while working with large number of order records?

UC has large amount of orders coming in from its online portal. Historically all order are assigned to a generic user.

Which 2 measures should data architect recommend to avoid any performance issues while working with large number of order records? Choose 2 answers:
A . Clear the role field in the generic user record.
B . Salesforce handles the assignment of orders automatically and there is no performance impact.
C . Create a role at top of role hierarchy and assign the role to the generic user.
D . Create a pool of generic users and distribute the assignment of memory to the pool of users.

Answer: A,C