Question: Which two distinct modules make up the Online Charging Function (OCF)?
Option 1: Session Based Charging Function (SBCF) and Policy Based Charging Function (PBCF)
Option 2: Event Based Charging Function (EBCF) and Offline Charging Function (OBF)
Option 3: Session Based Charging Function (SBCF) and Diameter Based Charging Function (DBCF)
Option 4: Session Based Charging Function (SBCF) and Event Based Charging Function (EBCF)
Explanation: The Online Charging Function (OCF) consists of two distinct modules, namely the Session Based Charging Function (SBCF) and the Event Based Charging Function (EBCF). These modules are responsible for online charging of network/user sessions and event-based online charging, respectively.