Match the series with the right expression. (Use the Maclaurin series.)

1. $\displaystyle \sum_{n=0}^\infty (-1)^n \frac{3^{2n+1}}{(2n+1)!}$

2. $\displaystyle \sum_{n=0}^\infty \frac{(-1)^n 3^{2n}}{(2n)!}$

3. $\displaystyle \sum_{n=0}^\infty \frac{3^n}{n!}$

4. $\displaystyle \sum_{n=0}^\infty \frac{(-1)^n 3^{-(2n+1)}}{2n+1}$

A. $\arctan(1/3)$
B. $\cos(3)$
C. $\sin(3)$
D. $e^3$