Correct option is A
Given:
Seven boxes, P, Q, R, S, T, U and V.
R is kept just below T.
V is kept just above Q, which is just above S.
Only three boxes are between V and U.
V is the topmost box.
From the given information arrangement will be:

So, from the given arrangement P is placed Immediately below S.
The correct answer is, immediately below S.
Thus, the correct option is, (a)