Which two actions are required when performing a unified in-service software upgrade (ISSU)?
(Choose two.)

A.
You must enable nonstop active routing (NSR).

B.
You must enable graceful Routing Engine switchover (GRES).

C.
You must disable graceful Routing Engine switchover (GRES) if the Layer 2 Control Protocol is
in use.

D.
You must disable nonstop bridging (NSB) if the Layer 2 Control Protocol is in use.