Which of the following descriptions about the characteristics of large concentration and small concentration is wrong?

Which of the following descriptions about the characteristics of large concentration and small concentration is wrong?
A . Large concentrated light splitting, FAT is set in the information distribution area in the corridor, and FAT can choose direct fusion or patch module (recommended patch module)
B . Small concentrated light splitting, the light splitter is centrally set in the large-capacity FAT or small FDT in the information distribution area, and the number is allocated according to the number of users
C . Set using first-order spectroscopy
D . Large-scale optical splitting, the optical splitters are centrally set on the large-capacity ODF/FDT in the information convergence area, and the number of optical splitters is configured according to the number of users

Answer: D