(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 V is ranked fifth, which of the following must be true ?

Answer: A. S scores the highest.

In terms of scores, we have :
V > P, P > Q  i.e. V > P > Q.
If R scores the highest, we have R > ...... > T,
If S scores the highest, we have S > ...... > Q or S > ...... > U.

If V ranks fift, P and Q coming before it will occupy sixth and seventh places respectively i.e. Q ranks least. So, S will score the highest.