Let \( O \) be the origin and let \( P Q R \) be an arbitrary trian...

Let \( O \) be the origin and let \( P Q R \) be an arbitrary triangle. The point \( S \) is such that
P
\( \mathrm{OP} \cdot \mathrm{OQ}+\mathrm{OR} \cdot \mathrm{OS}=\mathrm{OR} \cdot \mathrm{OP}+\mathrm{OQ} \cdot \mathrm{OS} \)
W
\( =\mathrm{OQ} \cdot \mathrm{OR}+\mathrm{OP} \cdot \mathrm{OS} \)
Then the triangle \( P Q R \) has \( S \) as its
(2017 Adv.)
(a) centroid
(b) orthocentre
(c) incentre
(d) circumcentre