hich of the following is true about the $7-$layer ISO Reference Model?

A$.$ It is based on the assumption that there are two co$-$operating systems wishing to communicate.

B$.$ Each layer of the model may add, to each data unit, control information to organise the

communication between the peer entities in the two remote systems.

C$.$ It is a framework to support the development and implementation of open communication

protocols.

D$.$ A and B are correct.

E$.$ A$,$ B and C are correct.