Simplify the rational expression.

$\frac{x^2(3x1{)}^2-x(3x1{)}^3}{(3x1{)}^6}$

$\frac{9x^{4}6x^3{x}^2-x}{(3x1{)}^3}$

$\frac{-2x^2-x}{(3x1{)}^4}$

$\frac{x^2-x}{(3x1)}$

$\frac{x}{(3x1{)}^4}$

None of these choices