The army developed the military occupational specialty system for tracking the weaponry skills in WWII.
These MOS system had various fields like communications department, gunnery and gunnery control department, field and coast artillery, air crew, security departments etc.
The selected soldiers are assigned their specific tasks and all the groups are organised by a alphanumeric code system.
Answer:
I believe it's b sorry if I'm wrong
a. because it is relatively stable
