contains a domain controller named DC1 that has the DNS Server server role installed.DC1 has a standard primary DNS zone for contoso.com.
You need to ensure that only client computers in the contoso.com domain will be able to add their records to the contoso.com zone.
What should you do first?()
A. Sign the contoso.com zone.
B. Modify the Security settings of DC1.
C. Modify the Security settings of the contoso.com zone.
D. Store the contoso.com zone in Active Directory.