Your network consists of a single Active Directory domain. The domain contains an organizational unit （OU） named SecureServers. The SecureServers OU contains a computer account for a server named Server1. You link a Group Policy object （GPO） to the SecureServers OU. In the GPO， you assign an IPSec policy that requires encryption for all communications. You notice that all communications to Server1 are unencrypted.You need to ensure that all communications to Server1 are encrypted immediately. What should you do？（）

A. On Server1， run gpudate.exe.
B. On Server1， run gpresult.exe.
C. From the properties of the GPO， enable the Enforced option.
D. From the properties on the SecureServers OU， enable the Block policy inheritance setting.