Which statement is correct about the number of available QoS system classes in FCoE?
A. It’s hard-set and cannot be disabled
B. It’s configurable, with an upper limit of 16
C. It’s hard-set but cannot disable best-effort and Fibre Channel
D. It’s hard-set but can disable all but one class
E. It’s configurable with an upper limit of eight
C is correct. Best effort/FC: You cannot disable this system class.
As per: https://www.cisco.com/c/en/us/td/docs/unified_computing/ucs/sw/gui/config/guide/3-0/b_UCSM_GUI_User_Guide_3_0/b_UCSM_GUI_User_Guide_3_0_chapter_010100.pdf
(Table 1: System Classes)