What is a possible cause for the Network Monitor server being in this state?

Under the “System Overview” in the Enforce management console, the status of a Network Monitor detection server is shown as “Running Selected.” The Network Monitor server’s event logs indicate that the packet capture and filereader processes are crashing.

What is a possible cause for the Network Monitor server being in this state?
A . There is insufficient disk space on the Network Monitor server.
B . The Network Monitor server’s certificate is corrupt or missing.
C . The Network Monitor server’s license file has expired.
D . The Enforce and Network Monitor servers are running different versions of DL

Answer: D