Which command revokes ACL-based write access for groups and named users on the file afile?
A . setfacI -x group: * : rx, user:*: rx afile
B . setfacl -x mask: : rx afile
C . setfacl ~m mask: : rx afile
D . setfacl ~m group: * : rx, user:*: rx afile
Answer: C