If $\begin{vmatrix}x-1&5x&7\\x^2-1&x-1&8\\2x&3x&0\end{vmatrix}$ = $ax^3+bx^2+cx+d$ then $c$ is equal to

Question

$(a)\;-1\qquad(b)\;12\qquad(c)\;15\qquad(d)\;17$