Option C: a composite number
$3 \times 11 \times 13 + 3 = 3(11 \times 13 + 1) = 3 \times 144 = 432$, which has factors other than 1 and itself, so it is a composite number.
The key is to take 3 common: $3(11 \times 13 + 1) = 3 \times 144$. Since the number has 3 as a factor (and is not 3 itself), it is composite. This directly applies the concept from Exercise 1.1, Q.6 of Chapter 1 — if a number can be expressed as a product of two integers both greater than 1, it is composite. Note: it is even (432), so option D is wrong; and it is divisible by 3, not 13, so B is wrong.