Question

based on the graph, which method of obtaining copper is likely the most cost - effective?
a using smelting has lower cleanup costs than bioleaching.
b using smelting is cheaper and generates more profit than bioleaching.
c bioleaching harvests the copper in a shorter time period than smelting.
d bioleaching is more expensive at first but the returns are much higher than smelting.

Explanation:

From the bar - graph, smelting has a lower cost (around 200,000 U.S. dollars per ton) compared to bioleaching (around 300,000 U.S. dollars per ton) and also has a profit (around 550,000 U.S. dollars per ton) while bioleaching has a higher profit (around 850,000 U.S. dollars per ton) but higher initial cost. Cost - effectiveness considers cost and profit. Smelting is cheaper and has a decent profit.

Answer:

B. Using smelting is cheaper and generates more profit than bioleaching.