Which of the following descriptions of protection ASON Level 2 is correct?

Which of the following descriptions of protection ASON Level 2 is correct?
A . 1+1 protection, 1 fault resistance, first recovery time <50ms
B . Permanent 1+1 protection, resistant to N-times faults, recovery time <50ms, availability 99.999%
C . Rerouting, resisting N-times faults
D . 1+1 protection + rerouting, 2N times fault resistance, recovery time <50ms

Answer: B