Question 3Of the following expressions, the one equal to $\dfrac{a^{-1}b^{-1}}{a^{-3}-b^{-3}}$ is:$\dfrac{a^2b^2}{b^2-a^2}$$\dfrac{a^2b^2}{b^3-a^3}$$\dfrac{ab}{b^3-a^3}$$\dfrac{a^3-b^3}{ab}$$\dfrac{a^2b^2}{a-b}$