A computer company can spend no more than $5,000 on raw materials for computer components. The raw materials cost $5 per ounce for aluminum and $20 per ounce for silver. To summarize the situation, a worker writes the inequality: 5a + 20s ≤ 5,000, where a is the number of ounces of aluminum material and s is the number of ounces of silver material. Which graph's shaded region shows the possible combinations of raw materials the company can buy?