What is true about groups in a Linux system? (Choose TWO correct answers.)
A. Each user may be a member of several groups. However, only one group is the user’s primary group.
B. Groups may have a password that allows users to join that group temporarily.
C. Each user can only be a member of one group at a time.
D. Group memberships are optional such that there may be users that do not belong to any group.
E. Groups can be nested meaning that one group can be a member of another group.