Your company has a single Active Directory forest that has an Active Directory domain named na.contoso. com A member server named Server2 runs the DNS server role. The Server2 DNS service hosts multiple secondary zones including na.contoso.com. You need to reconfigure Server2 as a caching-only DNS server. What should you do（）
- A Uninstall and reinstall the DNS service on Server2
- B Change all the DNS zones on Server2 to stub zones
- C Disable and then enable the DNS service on Server2
- D Delete the na.contoso.com DNS zone domain from Server2. Restart the DNS service on Server2.