Question: What type of services does the Charging Enablement Function (CEF) consume for the purpose of charging information collection?
Option 1: Only Nchf charging services
Option 2: Only management services exposed by other network functions
Option 3: Only services exposed by other network functions
Option 4: Both management services and services exposed by other network functions, in addition to Nchf charging services
Explanation: The Charging Enablement Function (CEF) is a consumer of multiple types of services for the purpose of charging information collection. It consumes Nchf charging services, as well as both management services and services exposed by other network functions. This allows the CEF to gather comprehensive charging information from various sources within the telecom network.