If the production of copper leads to increased pollution, which of the following best explains the underlying cause of the negative externality depicted in the externality graph?

The underlying cause of the negative externality in the production of copper is that the producers do not take into account the harmful effects their activities have on the environment and public health. When copper is mined and produced, it can lead to pollution that affects air and water quality, which can harm people and wildlife. This means that while the producers may benefit from selling copper, they are not paying for the damage caused by their pollution. For example, if a copper mine releases toxic waste into a river, the local community may suffer from contaminated drinking water, but the mine does not bear the cost of this harm. Therefore, the externality represents a situation where the true costs of production are not reflected in the price of copper, leading to overproduction and increased pollution.