If C is a super-authority over A and B, chances are pretty good that the relative parity of A and B is irrelevant. This also works if C is far under both A and B in a hierarchy. If A is the CEO of a multinational corporation and B is the deputy VP over domestic products and C is the high school intern working in the mail room... then the appropriate response from C to either A or B is "Yes, sir!" [* modified by gender if required]

Also if C knows A and B in a different context entirely. An example: My boss and I shop at the same supermarket, I have no expectations that my boss is treated differently by the cashiers.