Refer to the exhibit.

CE1 and CE2 cannot communicate through the service provider BGP peering is established between PE1 and PE2. IS-IS is the only routing protocol running in the service provider core. What step can be done to troubleshoot the issue?

A.	Switch the IGPs running in the core from IS-IS to OSPF to support a Cisco MPLS TE tunnel from PE1 to PE2.
B.	Configure BGP between CE and PE routers.
C.	Confirm that IS-IS is running with metric-style narrow.
D.	Verify the MPLS LSPs.