If a ROADM site adopts WSS + RMU configuration, which of the following impact on SOM is wrong?
A . If the RMU is used locally and the optical amplifier is used, the OSNR value of the SOM detection wavelength in the through direction will deviate from the actual value.
B . There is a local optical amplifier but no filter. The full-wave noise of the local optical amplifier affects the OSNR of the wavelength in the through direction.
C . The source and sink optical amplifiers at this site must be in the same network element.
Answer: A