Communication Has Often Evolved Through Co-Opting and Modifying Behaviors Used

Communication has often evolved through co-opting and modifying behaviors used in another context. For example, the elimination of wastes can also be used:

A) to strategically mark "ownership" of particular locations.
B) to let an intruder know where an individual's territory is so that a costly fight will not ensue.
C) to advertise to other individuals in order to attract mates.
D) All of these choices are correct.