Your company has a single Active Directory directory service forest with multiple domains. The  company has a main office with 1，000 users and a single branch office with 500 users. Each office is aseparate Active Directory site. The main office Active Directory site has two domain controllers with Global  Catalog services. Company employees must be able to work in both offices. You need to plan the  placement and configuration of domain controllers. 
What should you do？（）

You have a single Active Directory directory service domain with three sites named Site1，Site2，and  Site3. There are site links between all three sites，and replication between sites occurs every 30 minutes. You need to ensure that all replication traffic is routed through Site2. 
What should you do？（）