I put down (A). This is the only combination that will work out of the choices.
(A) If Q is in spot 1, then VW must go into spots 2 &3 because P must be in spot 4. If we tried to put VW into spot 5&6, then we would be missing one additional spot, since R-T have to go after VW in this conditional question.
Thus, the spots fill up like this:
Q V W P S R T
1 2 3 4 5 6 7
Why the others don't work:
(B) If R goes into spot 3, and we know that the chain must be VW-R-T, then we need at minimum 4 spaces available after P if we wanted to put VW after P. Since there are only 3 spots left after P, this won't work, and VW must go before P. Since R is taking up spot 3, then VW would must go into spots 1& 2. We run into a problem however with the Q-R rule. In this scenario, there is no space to fit Q in before R, which is sitting in spot 3.
(C) If S is in spot 2, then VW must go into 5 &6, which leaves only 1 additional spot, and we need a minimum of 2 spots after VW.
(D) If T goes into spot 6, then we know that S cannot be in either spots 5 or 7, so S must go into a spot before P. R has to go before T, so we can put R into spot 5. Once we have R in place we can decide where to put Q, since Q has to be before R. Because of where P is, Q will have to also go before P. And there we have a problem, because we also need spaces for VW. We run out of one extra space needed for V to fit in.
(E) If V goes into spot 6 and W, R, and T must come after V...then obviously we are three spaces short with V in the 6th spot.