If $u(x)=x^5-x^4+x^2$ and $v(x)=-x^2$, which expression is equivalent to $\left(\frac{u}{v}\right)(x)$ ?

A$x^3-x^2+1$

B$-x^3+x^2$

C$-x^3+x^2-1$

D$x^3-x^2$