单项选择题 A 2.5 Gb/s (OC-48 or STM-16) optical signal with a dispersion tolerance of 1200 ps/nm goes through fiber with 18ps/nm*km of dispersion. How many 15216-DCU-350 equivalents are needed for enough compensation after traveling 100 km?（）

单项选择题 Click the Exhibit button. What is the maximum allowable loss budget between the ONS 15216 Mux (left side) composite output and the ONS 15216 Demux (right side) composite input, with the optical values given in the exhibit? （）(Assume the worst case loss of 4.5 dB for 15216 200 GHz Mux/Demux and ignore power penalties or extra margin.)

多项选择题 What are two important considerations when using 2- or 4-channel 15216 OADMs?（） (Choose two.)