The largest number by which the expression $n^3 - n$ is divisible for all possible integral values of $n$, is:
$\textbf{(A)}\ 2 \qquad\textbf{(B)}\ 3 \qquad\textbf{(C)}\ 4 \qquad\textbf{(D)}\ 5 \qquad\textbf{(E)}\ 6$
Factoring the polynomial gives $(n+1)(n)(n-1)$ According to the factorization, one of those factors must be a multiple of two because there are more than 2 consecutive integers. In addition, because there are three consecutive integers, one of the integers must be a multiple of 3.  Therefore $6$ must divide the given expression.
Plugging in $n=2$ yields $6$.  So the largest possibility is $6$.
Clearly the answer is $\boxed{\textbf{(E)} \ 6}$