Refer to the exhibit. Which statement about this neighbor of R1 is true?
R1# show ipv6 neighbor
IPv6 Address Age Link-layer AddrState Interface
FE80::21E:79FF:FFAB:3141 2 001e.79ab.3141STALE Gi0/1

A.
OSPFv3 adjacency has been lost, which causes the neighbor to be considered Stale.

B.
Aggregate global addresses are always used between IPv6 neighbors.

C.
OSPFv3 adjacency will not work between link-local addresses.

D.
R1 used ICMP to learn about this neighbor.