What should the size of the Ethernet bandwidth be per call?

An engineer implements a new Cisco UCM based telephony system per these requirements:

• The local Ethernet bandwidth is sized based on the total bandwidth per call

• A G.736 codec is used.

• The bit rate is 64 kbps

• The codec sample interval is 10 ms.

• The voice payload size is 160 bytes per 20 ms.

What should the size of the Ethernet bandwidth be per call?
A . 31 2 kbps
B . 38.4 kbps
C . 55.2 kbps
D . 87.2 kbps