Which choice best defines events and event handlers?

Which choice best defines events and event handlers?

A.
An event can be an action initiated by the user, and an event handler specifies how JavaScript will react to the action.

B.
An event is an action initiated by the operating system, and an event handler is a function defined by the user.

C.
An event handler can be an action initiated by the user, and an event specifies how JavaScript will react to the action.

D.
An event is initiated by an error in JavaScript, and an event handler will attempt to bypass the error and continue.