Which configuration needs to be added or changed?

Refer to the exhibit.

An administrator is adding IPv6 addressing to an already functioning tunnel. The administrator is unable to ping 2001:DB8:100::2 but can ping 209.165.200.226.
Which configuration needs to be added or changed?

A.
No configuration change is necessary. Everything is working correctly.

B.
OSPFv3 needs to be configured on the interface.

C.
NHRP needs to be configured to provide NBMA mapping.

D.
Tunnel mode needs to be changed to GRE IPv4.

E.
Tunnel mode needs to be changed to GRE IPv6.