Need some help with a home work lab - OSPF connecting adjacency routers!

in CCNA & CCENT
Reading through my book and i didn't see anything like this, so im not sure why its in my home, but they are trying to connect a class a with a class b and forming a network together, is this even possible?
Here is my packet tracer file
https://www.dropbox.com/s/1k9snsazv0spiup/LabE04.pkt?dl=0
Could someone tell me thats done CCNA if this is even possible or if i'm missing somethikng? I am doing it exactly how it is in the lab and am not missing anything!
So frustrating when the labs they give you dont even work right out of the box
Here is my packet tracer file
https://www.dropbox.com/s/1k9snsazv0spiup/LabE04.pkt?dl=0
Could someone tell me thats done CCNA if this is even possible or if i'm missing somethikng? I am doing it exactly how it is in the lab and am not missing anything!
So frustrating when the labs they give you dont even work right out of the box
Comments
Also in order for a serial link to make a connection the serial links both need to be in the same subnet or they won't pass traffic.