方程组 $\left\{\begin{array}{l}x+y=5 \\ 2 x-y=1\end{array}\right.$ 的解为
A. $\left\{\begin{array}{l}x=2 \\ y=3\end{array}\right.$
B. $\left\{\begin{array}{l}x=3 \\ y=2\end{array}\right.$
C. $\left\{\begin{array}{l}x=1 \\ y=4\end{array}\right.$
D. $\left\{\begin{array}{l}x=4 \\ y=1\end{array}\right.$