An electronics company can spend no more than $4,000 on raw materials for circuit boards. the raw materials cost $10 per ounce for copper and $20 per ounce for silver.

to summarize the situation, a worker writes the inequality:

10c + 20s ≤ 4,000, where c is the number of ounces of copper 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?