CEMC Cayley, 2011

Geometry Difficulty 2.0 Junior Find the answer Canada

The points $Q(1, -1)$ , $R(-1, 0)$ and $S(0, 1)$ are three vertices of a parallelogram. The coordinates of the fourth vertex of the parallelogram could be

(A) $(-2, 2)$ (B) $(0, -1)$ (C) $(0, 0)$ (D) $\left(\frac{3}{2}, \frac{1}{2}\right)$ (E) $(-1, 1)$

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