Your network contains an Active Directory domain named contoso.com.
You deploy Active Directory Certificate Services (AD CS).
Your company, which is named Contoso, Ltd., has a partner company named Fabrikam, Inc. Fabrikam also deploys AD CS.
Contoso and Fabrikam plan to exchange signed and encrypted email messages.
You need to ensure that the client computers in both Contoso and Fabrikam trust each other's email certificates. The solution must prevent other certificates from being trusted and minimize administrative effort.
What should you do?
More than one answer choice may achieve the goal. Select the BEST answer.