\( 0.9 \quad \) If \( \Delta_{r}=\left|\begin{array}{ccc}r & n & 6 \\ r^{2} & 2 n^{2} & 4 n-2 \\ r^{3} & 3 n^{3} & 3 n^{2}-3 n\end{array}\right| \), then \( \sum_{r=0}^{n-1} \Delta_{r} \) equals to
(1) \( n^{2}(n+2) \)
(2) \( n(n+2)^{2} \)
(3) \( \frac{1}{12} n\left(n^{3}+2\right) \)
(4) none of these
