User-718146471 posted
Well, for starters, this will require changes to active directory itself, by enabling OU auditing. Once enabled, you will need to view the Event Viewer, possibly on the domain controller.
Here's an article to get you started.
https://www.lepide.com/how-to/audit-organizational-units-changes-in-active-directory.html
You may need help from your AD Team to get this turned on. However, it will show only what is future from the point of turning the auditing on. If that is already enabled, then you can turn your attention to using C# to read/evaluate the audit log in Event
Viewer.