Let \( P \) be the foot of the perpendicular from the point \( Q(10,-3,-1) \) on the line \( \dfrac{x-3}{7}=\dfrac{y-2}{-1}=\dfrac{z+1}{-2} \). Then the area of the right-angled triangle \( PQR \), where \( R \) is the point \( (3,-2,1) \) is:
\( 8\sqrt{15} \)
\( 3\sqrt{30} \)
\( \sqrt{30} \)
\( 9\sqrt{15} \)
