What is the purpose of an event based undercover agent (UCA) in IBM Business Process Manager?

What is the purpose of an event based undercover agent (UCA) in IBM Business Process Manager?
A . It ensures that timed events are triggering on schedule.
B . It monitors the transfer of tracking events into the Performance Data Warehouse (PDW).
C . It synchronizes shared business objects across one or more Business Process Definitions (BPD’s).
D . It calls a service to handle a message event or a content event targeted for a Business Process Definition (BPD).

Answer: D

Explanation:

Reference: http://www.ibm.com/support/knowledgecenter/SSV2LR/com.ibm.wbpm.wle.editor.doc/topics/ using_undercover_agents.html