Quick button syntax question

Hi everyone

I’d like to keep all my button code on the made timeline as a discipline I’d like to start. I have a button instance named aboutBtn in a movie clip. That movie clip is nested in another movie clip. That final movie clip is on the main timeline and given an instance name of menu.

Would my syntax for onRelease then be:

_root.menu.aboutBtn.onRelease = function() {

Or would it be:

_root.aboutBtn.onRelease = function() {

Or:

_root.menu.aboutBtn.onRelease…

What would the syntax to give that button an action be?