What is possibly true concerning Traffic contract, Traffic shaping, and Traffic policing in ATM networks?

A.
They are parameters of PNNI set during PNNI configuration.

B.
They are types of SVCs.

C.
They are types of PVCs.

D.
They are forms of QoS features used in ATM networks.

E.
They are only used between ATM switches to control traffic flows.