Which operational command on PE1 helps troubleshoot this problem?

Referring to the exhibit, Customer A is complaining that no OSPF routes are being received across your Layer 3 VPN. You suspect that a problem exists with the PE-CE protocol. The core network is operational.Which operational command on PE1 helps troubleshoot this problem?

A.
show ospf neighbor

B.
show bgp summary

C.
show ospf neighbor instance customer-a

D.
show bgp summary instance customer-a