How frequent are updates of WebFilter on-box database within the ProxySG?

A.
Every 5-20 minutes during the time intervals set in the Management Console

B.
When the previous database subscription period ends, approximately once every 60 days

C.
Once every day, the specific time is configurable via Management Console

D.
Only when the administrator presses button Download now, to downloads a new bcwf.db file to
the ProxySG

Explanation: