Which expression is the simplified form of 1x−2−1x2−4\frac{1}{x-2} - \frac{1}{x^2-4}x−21−x2−41?
x−1x2−4\frac{x-1}{x^2-4}x2−4x−1
x−3x2−4\frac{x-3}{x^2-4}x2−4x−3
x+1x2−4\frac{x+1}{x^2-4}x2−4x+1
x+2x2−4\frac{x+2}{x^2-4}x2−4x+2