How does Protection Level: N+2:1 differ from Protection Level N+2?

A.
N+2:1 allows the cluster to sustain the loss of two drives or one node without data loss

B.
N+2 allows the cluster to sustain the loss of two drives or one node without data loss

C.
N+2 protection levels are RAID 6 equivalents, where N+2:1 protection levels are RAID 5
equivalents

D.
N+2:1 protection levels are RAID 6 equivalents, where N+2 protection levels are RAID 5
equivalents