CEMC Gauss (Grade 8), 2001

Lines $PS$, $QT$ and $RU$ intersect at a common point $O$, as shown. $P$ is joined to $Q$, $R$ to $S$, and $T$ to $U$, to form triangles. The value of $\angle P + \angle Q + \angle R + \angle S + \angle T + \angle U$ is

(A) $450^\circ$ (B) $270^\circ$ (C) $360^\circ$ (D) $540^\circ$ (E) $720^\circ$