If $n=7$, which of the following expressions is equal to an even integer?
(A) $9 n$
(B) $n+8$
(C) $n^{2}$
(D) $n(n-2)$
(E) $8 n$
When $n=7$, we have

$$
9 n=63 \quad n+8=15 \quad n^{2}=49 \quad n(n-2)=7(5)=35 \quad 8 n=56
$$

Therefore, $8 n$ is even.

We note that for every integer $n$, the expression $8 n$ is equal to an even integer, since 8 is even and the product of an even integer with any integer is even.

If $n$ were even, then in fact all five choices would be even. If $n$ is odd, only $8 n$ is even.

ANsWer: (E)