 By  Universal Domain and resoluteness, \(V\) must select exactly one of  \(A\), \(B\), or \(C\) as the winner.   Assume that \(V\) select \(A\)  as the winner (the argument when \(V\) selects the other candidates is similar).   Now, consider the profile in which every  voter swaps candidate \(A\)  and \(B\) in their rankings:  