An expression that produces the values in the second row of the table shown, given the values of $n$ in the first row, is
(A) $3 n-2$
(B) $2(n-1)$
(C) $n+4$
(D) $2 n$
(E) $2 n-1$

| $n$ | 1 | 2 | 3 | 4 | 5 |
| :---: | :--- | :--- | :--- | :--- | :--- |
| value | 1 | 3 | 5 | 7 | 9 |
When $n=4$, we are looking for an expression that produces a value of 7 .

The results of substituting $n=4$ into each expression and evaluating are shown below.

| Expression | Value |
| :--- | :--- |
| (A) $3 n-2$ | $3(4)-2=12-2=10$ |
| (B) $2(n-1)$ | $2(4-1)=2(3)=6$ |
| (C) $n+4$ | $4+4=8$ |
| (D) $2 n$ | $2(4)=8$ |
| (E) $2 n-1$ | $2(4)-1=8-1=7$ |

Since $2 n-1$ is the only expression which gives a value of 7 when $n=4$, it is the only possible answer. We check that the expression $2 n-1$ does give the remaining values, $1,3,5,9$, when $n=1,2,3,5$, respectively.

(Alternately, we may have began by substituting $n=1$ and noticing that this eliminates answers (B), (C) and (D). Substituting $n=2$ eliminates (A). Substituting $n=3, n=4$ and $n=5$ confirms the answer (E).)

ANswer: (E)