A.enable concatenation on the non-root bridge only
B.enable concatenation on the root bridge only
C.enable concatenation on both the root bridge and non-root bridge
D.enable concatenation on the root bridge and set it as desirable on the non-root bridge
E.set concatenation as desirable on the root bridge and enable it on the non-root bridge

A.x.509 certificate
B.generic token card
C.pre shared key
D.protected access credential