If \(\begin{vmatrix} (a_1 - b_1)^2& (a_1 -b_2)^2&(a_1 - b_3)^2\\(a_2 - b_1)^2&(a_2 -b_2)^2&(a_2 - b_3)^2\\(a_3-b_1)^2&(a_3 - b_2)^2&(a_3 - b_3)^2\end{vmatrix}\) = k(a1 – a2)(a2 – a3)(a3 – a1)(b1 – b2)(b2 – b3)(b3 – b1), then k is equal to
(a) 1
(b) 2
(c) 4
(d) 8