2. A rectangular frame is made using two types of metal materials, with the longer side and the shorter side using metal materials priced at 3 yuan $/ \mathrm{m}$ and 5 yuan $/ \mathrm{m}$, respectively. The length and width must be integer meters. Given a budget of no more than 100 yuan, the maximum area enclosed by the rectangular frame is ( ).
A. $40 \mathrm{~m}^{2}$
B. $30 \mathrm{~m}^{2}$
C. $20 \mathrm{~m}^{2}$
D. None of the above
2. A

Let the length and width of the rectangle be $x$ meters and $y$ meters, respectively. From the problem, we know that $2(3 x+5 y) \leqslant 100$ which simplifies to $3 x+5 y \leqslant 50$.
When $x=8, y=5$, $3 x \cdot 5 y$ is maximized, and the maximum value of $x y$ is 40.