An OU structure in your domain has one OU per department, and all the computer and user accounts are in their respective OUs. You have configured several GPOs defining computer and user policies and linked the GPOs to the domain. A group of managers in the Marketing Department need different policies from the rest of the Marketing Department users and computers, but you don't want to change the top$-$level OU structure. Which of the following GPO processing features are you most likely to use?

a$.$ Block inheritance

b$.$ GPO enforcement

c$.$ WMI filtering

d$.$ Loopback processing