I'm working on finishing my basement, and I need help verifying that some drains are what I think they are. I'm fairly sure the original builder left some capped drains so the basement could be finished. There are two caped PVC pipes going into my concrete slab - one 4" and one 2". I'm 99% sure the 4" is for a toilet, and the 2" is for a sink drain. The only thing is, the 2" has a cutout around it (about 6"x8") in the slab, but the 4" goes straight into the concrete. I've attached a picture, can anyone help me ID these before I cut into them? Thank you very much!