Out of 5 undisturbed horizontal beds of sedimentary rock, we can say that

A. the top layer is oldest

B. the lowest layer is oldest

C. there is no way of knowing which is oldest

D. the 2nd and 3rd are younger than the top layer.

B:the lowest layer is the oldest

the layers above are newer because they were formed on top of them. the lower the layer the older it is. similar with rings of a tree. the smaller rings are older than the bigger ones because the smaller rings were formed first then the bigger one grew around it