Where can an administrator specify the notification action to be taken by the firewall in the event

Where can an administrator specify the notification action to be taken by the firewall in the event
that available disk space drops below 15%?

A.
SmartView Monitor > Gateway Status > Threshold Settings
B. SmartView Tracker > Audit Tab > Gateway Counters

C.
SmartView Monitor > Gateway Status > System Information > Thresholds

D.
This can only be monitored by a user-defined script.