16. How many of the following positive integers are divisible by 24 ?
$$
2^{2} \times 3^{2} \times 5^{2} \times 7^{3} \quad 2^{2} \times 3^{2} \times 5^{3} \times 7^{2} \quad 2^{2} \times 3^{3} \times 5^{2} \times 7^{2} \quad 2^{3} \times 3^{2} \times 5^{2} \times 7^{2}
$$

A 0
B 1
C 2
D 3
E 4
16. B The prime factorisation of $24=2^{3} \times 3$. Therefore all multiples of 24 must include both $2^{3}$ and 3 in their prime factorisation. Of the options given, only the last includes $2^{3}$. As it is also a multiple of 3 , it is a multiple of 24 .