Find the number of arrangements of all the letters in the word 'CAT'.

1. 'CAT' has 3 DISTINCT letters: C, A, T. 2. Number of ways to arrange $n$ distinct objects in a row: $n! = 3! = 6$. 3. Enumerate: CAT, CTA, ACT, ATC, TAC, TCA — six arrangements. 4. Option A is just $n$. Option C is $n^2$. Option D is $n^n$ (would apply to selection WITH repetition). _Source: syllabus Mathematics, Ch 6, §6.3 + Examples, p. 5–7._