The correct answer is C. Biological
Explanation:
A biological hazard refers to a biological substance such as viruses, insects, fungus, etc. that can affect humans or other animals' health negatively. In the case of Kris and James, they are exposed to a biological hazard because stagnant water is commonly used by mosquitos to place eggs, this leads to a lot of mosquitos around stagnant waters and therefore a higher risk of mosquito-transmitted diseases such as malaria. Besides this, stagnant water is highly polluted and includes bacteria and parasites that are harmful.
