Identify the word that cannot be formed using the letters of the word 'NATIONAL'.

Let's examine the letters available in the word 'NATIONAL': N, A, T, I, O, N, A, L. (Notice there are two N's, two A's, one T, one I, one O, and one L).
* 'NATION' uses N, A, T, I, O, N (all available).
* 'ANT' uses A, N, T (all available).
* 'ALONE' requires the letter 'E', which is completely absent in 'NATIONAL'. Therefore, it cannot be formed.
* 'LOAN' uses L, O, A, N (all available).