I would say all of them. This guy has a very over inflated opinion as to the capabilities of an AR-15. Also, an AR is a medium range rifle and a good shooter doesn't need ANY optics with it other than, perhaps, a night vision scope. At 100 to 150 yards my accuracy with iron sights on a AR is pretty much the same as with a scope but the ability to acquire a target quickly, especially a moving target, is much better with iron sights.
Give me a G3 with a scope and you got some serious hurt going down range. This guy forgets if the intended target knows a goon strike team is coming this invites plenty of places for a bushwack. Throw in just two or three deer hunters, especially if they have any military experience, with scoped hunting rifles and a goon team could be utterly decimated without ever having seen the faces of their killers.