Which one of the following is the BEST definition of an event?

A.
Any change of state that has significance for the management of a configuration item
(CI) or IT service

B.
An unplanned interruption to an IT service or a reduction in the quality of an IT service

C.
The unknown cause of one or more incidents that have an impact on an IT service

D.
Reducing or eliminating the cause of an incident or problem