Let P, Q, R, S be the points on the plane with position vectors –2i – j, 4i, 3i + 3j and –3i + 2j respectively. The quadrilateral PQRS must be a
(a) parallelogram, which is neither a rhombus nor a rectangle
(b) square
(c) rectangle but not a square
(d) rhombus but not a square.