the 2nd floor of a building is going to be divded to form 4 class rooms each with seating for 40 people in each class room this totals 160 people for the total floor.must the guidelines.of ariticle 518 .2 and518 .4 apply because there are over 100 people on that floor.
As long as you don't use NMC, you should be alright, no matter how it's classified. Whether it's an A or not could also be determined by the path of egress. (if each room had it's own exit for example). Also remember that an Assembly per the building code is 50, but you only have to wire it as such at 100, but you will have other issues such as egress lighting and exterior landing lighting, exit signs, etc.