Which action corrects the problem?

Refer to the exhibit.

A network engineer configured routers R1 and R5 to run in IS-IS Level 1 mode and router R6 to run in IS-IS Level 2 mode. All other routers are running as Level 1 / Level 2 routers. An engineer expects traffic from R1 to R6 to pass via R2, but IS-IS routing has calculated the best path via R4 .

Which action corrects the problem?
A . Configure all routers as Level 1 routers.
B . Remove the link metric for the link from router R1 to router R2.
C . Change the link metric for the link from router R1 to router R2 to 1.
D . Configure all routers as Level 1 / Level 2 routers.

Answer: C

Explanation:

The default link metric for IS-IS is 10, so changing the link from R1 to R2 to 1 will change the overall metric to R6 to 9 (8+1).