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.
