(i). Seven students P, Q, R, S,  T, U and V take a series of tests.
(ii). No two students get similar marks.
(iii). V always scores more than P.
(iv). P always scores more than Q.
(v). Each time either R socres the highest and T gets the least, or alternatively S scores the highest and U or Q scores the least. If S is ranked sixth and Q is ranked fifth, which of the following can be true ?

D. U IS RANKED THIRD OR FOURTH.