Which function does the Cisco Serving Gateway perform in a basic EPC network?

Which function does the Cisco Serving Gateway perform in a basic EPC network?

A.
The SGW is responsible for authentication of the subscribers connecting to EPC network.

B.
The SGW is a termination point in the network for Internet access.

C.
The SGW forwards data packets from subscribers toward the PDN gateway.

D.
The SGW is responsible for assigning the IP address to the subscriber.