The gain of the OAU board is 23db, and 1% of the total output power of the OAU board is used for MON detection. The output optical power of the MON port is -8dbm now. What is the input optical power of the IN port of the OAU board?
A . -11dbm
B . -13dbm
C . -15dbm
D . -21dbm
Answer: A