Which option describes how PCRF knows the amount of QoS that is needed for a Voice
over LTE call?

A.
PCRF obtains the bandwidth information over the Sy interface.

B.
PCRF obtains the bandwidth information over the Rx interface from P-CSCF.

C.
PCRF obtains bandwidth information from the TAS.

D.
PCRF has the all the bandwidth information always hard-coded in its configuration.