Which of the following expressions is equivalent to 1x−y−x2+y2x3−y3\frac{1}{x-y} - \frac{x^2+y^2}{x^3-y^3}x−y1−x3−y3x2+y2?
xyx3−y3\frac{xy}{x^3-y^3}x3−y3xy
x−yx2+xy+y2\frac{x-y}{x^2+xy+y^2}x2+xy+y2x−y
xyx2+xy+y2\frac{xy}{x^2+xy+y^2}x2+xy+y2xy
1x2+xy+y2\frac{1}{x^2+xy+y^2}x2+xy+y21