Which corrective action must be taken on the switch infrastructure to correct this issue?

A network administrator is troubleshooting an OSPF routing issue. There are two paths to a destination network from one switch. In addition, one path is comprised of four 1 Gb links.

The other path is comprised of two 1 Gb and two 100 Mb links. The administrator ran several trace routes and notices that the packets are swapping back and forth between the two paths.

Which corrective action must be taken on the switch infrastructure to correct this issue?
A . Manually specify the OSPF Router ID on each switch within the path.
B . Break the paths into multiple OSPF areas.
C . Change the reference speed used by OSPF in cost calculations on all switches within the path.
D . Switch all routing protocols to RIPv2.

Answer: C