How many calls can be made?

Given a VoIP network with these attributes:
Codec: G.711
WAN bandwidth: 768Kbps
Packet Header: 6 bytes
Payload: 160 bytes
CRTP: No
How many calls can be made?

A.
7 calls

B.
8 calls

C.
9 calls

D.
11 calls

E.
13 calls