Determine a region of the xy-plane for which the given differential equation would have a unique solution whose graph passes through a point (x0, y0) in the region.
dy dx = sqrt(xy)
there is a unique solution in any rectangular region where x > 0 and y > 0 or x > 0 and y < 0.
there is a unique solution in the entire xy-plane.
there is a unique solution in the region x ≤ y.
there is a unique solution in any rectangular region where x < 0 and y > 0.
there is a unique solution in any rectangular region where x > 0 and y > 0 or x < 0 and y < 0.