A conservative vector field is given by \mathbf{F}=-y^{2} \mathbf{i}-2 x y \mathbf{j}+e^{-z} \mathbf{k} Select the option that gives a potential function for F. \mathbf{A} \quad U(x, y, z)=-x y^{2}-e^{-z} U(x,
y, z)=2 x y+y^{2}-e^{-z} \mathbf{C} \quad U(x, y, z)=x y^{2}+e^{-z} \text { D } U(x, y, z)=2 x y^{2}+e^{-z}