Find $(a + b)^4 - (a - b)^4.$ Hence, evaluate $( \sqrt3 + \sqrt2)^4 - (\sqrt 3 - \sqrt 2)^4$.

Question

$\begin{array}{1 1} 40 \sqrt 6 \\ 20 \sqrt 6 \\ 40 \sqrt 3 \\ 20 \sqrt 3 \end{array}$