1962 AHSME Problem 9

When x^9-x is factored as completely as possible into polynomials and monomials with integral coefficients, the number of factors is:

\textbf{(A)}\ \text{more than 5} \qquad \textbf{(B)}\ 5 \qquad \textbf{(C)}\ 4 \qquad \textbf{(D)}\ 3 \qquad \textbf{(E)}\ 2

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.