Which reference point connects the PCRF in the 3GPP EPC to the HSGW in the 3GPP2 eHRPD access network?

Which reference point connects the PCRF in the 3GPP EPC to the HSGW in the 3GPP2
eHRPD access network?

A.
Pi

B.
A101

C.
Gxa

D.
STa

E.
S2a

F.
A11