A copper mining operation discharges waste products into a river and causes higher costs and discomfort to downstream users of the water for which they are not compensated. In this case:
there is an external benefit to society from copper production.
too much of society's resources is being used to produce copper.
the optimal amount of society's resources is being used to produce copper.
too little of society's resources is being used to produce copper.

Too much of society's resources is being used to produce copper.

Explanation:

Mining operation is a process whereby the natural resources embedded in the soil are being removed for the usefulness of the populace.

The process of mining involves the degradation of the soil, which can or will render that part of the land almost useless. This means that, the land is inhabitable for most of the natural habitant organisms, and not suitable for agriculture.

The waste products from the mining process are also channeled to water bodies or left unattended to at the mining site, thereby creating pollution to the environment.

In this case, copper mining operation will render the part of the land in the society useless while the waste products channeled to the water creates discomfort to the people residing in the society. This is because, the water won't be useful for domestic purposes and , also kills the organisms such as fish in the water. Therefore, the residents will be forced to look elsewhere for water which is extra cost. And no compensation is given to the society most times.

we need the diagram to answer this correctly.

marginal cost is a microeconomic measure that us to evaluate the extent to which the level of production of a good is sustainable in accounting, that is, to how many quantities the company plans to profit from the production of the good.

the concept of marginal cost is simple, it means the cost of producing one more item. for example, in the case of pies, the marginal cost is the cost of producing one more pie than those that have already been produced.

it is important to understand that productive activity influences marginal cost. the marginal cost of some goods can be very high, while others may be insignificant. for example, the marginal cost of producing an extra plane is very high. already the marginal cost of a water company to provide 1l more water is derisory.

in the case of pies, the cost involves the inputs, the labor and the fixed cost, which involves the fixed space of the bakery. the level of production initially has the marginal cost decreasing because there is space and manpower available. however, to produce more you have to hire more workers and buy more inputs. if physical space is limited, workers will conflict with places, inputs and their productivity will decrease, meaning there is an optimum point of production for each level of space and manpower. from this point on, the productivity of the workers will be getting smaller because of lack of space, so that the marginal cost of producing one more pie will be increasing. so, although you have not posted the chart, but if you have the answer, you can see that my explanation goes according to the marginal cost curve that will increase from the 4th pie, answer (c).