Which expression is equivalent to x3y−2x−1y4\frac{x^3 y^{-2}}{x^{-1} y^4}x−1y4x3y−2?
x4y−6x^4 y^{-6}x4y−6
x4y6\frac{x^4}{y^6}y6x4
x2y2x^2 y^2x2y2
1x4y6\frac{1}{x^4 y^6}x4y61