Assume that the PEs are separated by Multiple P routers.
How many labels should the ingress PE push for 6PE functionality?

A.
1

B.
None

C.
3

D.
2

E.
It depends on the numbers of hops between the ingress and egress PE.

Explanation:
A PE device on receiving the IPv6 prefix from CE by routing protocol will assign a label and
advertise through BGP to other PE devices which in turn will be advertised to remote CE devices.
This label information will be used to switch the packet through MPLS cloud. 6PE implementation
will have minimum 2 labels imposed, top label being the one to identify the remote PE while
bottom label to identify the IPv6 prefix.