What should you do?

Your network contains an Active Directory forest named adatum.com.
A partner organization has an Active Directory forest named contoso.com.
Adatum.com contains an Active Directory Rights Management (AD RMS) cluster installed on a server named adat1.adatum.com.
Contoso.com contains an Active Directory Rights Management Services (AD RMS) cluster installed on a server named cont1.contoso.com.
You need to allow the AD RMS cluster in adatum.com to accept rights account certificates (RACs) from contoso.com.
What should you do?
A. In contoso.com, import the trusted user domain file from adat1.adatum.com
B. In adatum.com, import the trusted publishing domain file from adat1.adatum.com
C. In contoso.com, import the trusted publishing domain file from cont1.contoso.com
D. In adatum.com, import the trusted user domain file from cont1.contoso.com