Can A. be very explosive. B. increase the chances of a volcanic eruption. C. release toxic elements into the groundwater or surface water. D. decrease the amount of nonrenewable resources available.

The best answer is C. Tailings are dangerous because they can release toxic elements into the groundwater or surface water. Tailings are the waste materials after the process of extracting the valuable part in a mine. These waste materials have a big potential to destroy the environment because they can release toxic substances which include arsenic and mercury. These tailings can contaminate water bodies.