"It's not wise for you know everything as that may in fact limit your own path but I guess I can reveal the basics." After an intense training session Maya decided to answer Frost's query, allowing him to know the basics of what separated the upper ranks.
"Now that you've reached B-rank you probably understand that the main dividing factor between C-rank and B-rank is being able to utilise and harness your own aura." Maya applied a rudimentary version of aura for display purposes.