What is true about UIDs and GIDs?

What is true about UIDs and GIDs?

A.
UIDs and GIDs share a common number space. Each time a new user or group is created, the
next free ID is assigned.

B.
The first four digits of each UID are the GID of the primary group of that user.

C.
The GID of a group is always the sum of the UIDs of its members.

D.
The number space is split up. UIDs usually reside in the range from 0 to 32767 while GIDs
reside in the range from 32768 to 65535.

E.
There are distinct number spaces for UIDs and GIDs, i.e. the same number may be used as
both a UID and a GID.

Explanation: