2. Which of the following numbers can be obtained by summing the squares of two integers that are multiples of 3?
(A) 450
(B) 300
(C) 270
(D) 483
(E) 189
(2) The correct answer is $(A)$.

Indeed, if $n$ is a number that is the sum of the squares of two numbers $3 h, 3 k$ which are integers and multiples of three, then it must be that $n=9\left(h^{2}+k^{2}\right)$; hence $n$ is divisible by 9. Of the possible answers, only 450, 270, and 189 are divisible by 9. Dividing these numbers by 9, we get 50, 30, and 21. Of these, only $50=1^{2}+7^{2}=5^{2}+5^{2}$ can be expressed as the sum of two squares.

Question proposed by Gabriele Manganelli.