What should a Data architect implement to make changes efficiently?

Universal Containers (UC) is going thought major reorganization of their sales team. This would require changes to a large a number of group members and sharing rules. UCs administrator is concerned about long processing time and failure during the process.

What should a Data architect implement to make changes efficiently?
A . Log a case with salesforce to make sharing rule changes.
B. Enable Defer Sharing Calculation prior to making sharing rule changes.
C. Delete old sharing rules and build new sharing rules
D. Log out all users and make changes to sharing rules.

Answer: B