Attach diagram

The diagram does not include the cost of the links. We can't give answer how the cost change from 30 to 40 to 50.

Assumption;

All link cost is 10 except the link between the router in the center and the bottom which is 20.

A. OSPF cost 30

The path is the vertical line between the top and the bottom router = 10 + 20 = 30

B. OSPF cost 40

Zigzag line in the left = 10 + 10 + 10 + 10 = 40

C. OSPF cost 50

Zigzag lin in the right plus the bottom line = 10 + 10 + 10 + 20 (or 10 + 10 + 10 + 10 + 10 +10) = 50

Please complete your diagram. Put OSPF cost in all the lines and put a name in all the routers.

Sorry, All links are ethernet links which i think ospf cost is 10

Depends, it could be.

1. Ethernet

2. FastEthernet

3. GigabitEthernet

4. Manually configured the ospf cost to manipulate route path (recommended)

So its still best to put the cost for the links in the diagram.