If the roots of the equation $(c^2-ab)x^2-2(a^2-bc)x+b^2-ac=0$ are equal,then $a^3+b^3+c^3=$______

Question

$\begin{array}{1 1}(A) \; abc\\(B)\;a^3b^3c^3\\(C)\;3abc^3 \\(D)\;3abc \end{array}$