How do you resolve this problem without causing other security issues?

You receive a notification that long-lasting Telnet connections to a mainframe are dropped after an
hour of inactivity. Reviewing SmartView Tracker shows the packet is dropped with the error:
Unknown established connection
How do you resolve this problem without causing other security issues? Choose the BEST
answer.

A.
Increase the service-based session timeout of the default Telnet service to 24-hours.
B. Ask the mainframe users to reconnect every time this error occurs.

C.
Increase the TCP session timeout under Global Properties > Stateful Inspection.

D.
Create a new TCP service object on port 23 called Telnet-mainframe. Define a service-based
session timeout of 24-hours. Use this new object only in the rule that allows the Telnet
connections to the mainframe.