Mercury in Fish Mercury Is a Highly Toxic Metal Found in Neon Signs

Mercury in Fish
Mercury is a highly toxic metal found in neon signs, fluorescent lights, older thermometers, and certain kinds of telescopes. It can also be found in something that many people eat on a regular basis: fish. The mercury we might find in a can of tuna is most likely an indirect result of the coal industry. Mercury, which is naturally found in coal, is released into the air when coal is burned. It finds its way into waterways via mercury-laced rain.
Mercury accumulates in certain kinds of fish through a process called biomagnification. Biomagnification occurs when a substance enters the food chain in small amounts at the very bottom and then increases in concentration in animals higher up on the food chain. Once a fish eats another creature containing mercury, the mercury does not leave that fish's body, but instead is stored in fat. Therefore, the mercury continually accumulates as more mercury-contaminated fish are eaten.
Despite the toxicity of mercury and the widespread nature of fish contamination, there is no need for the public to be overly apprehensive. Many popular fish, such as salmon, catfish, or tilapia, are generally safe to eat. Other fish, especially tuna and grouper, should only be eaten in moderation. Young children and pregnant women should be especially cautious about how many servings of mercury-contaminated fish they have per week. It is recommended that people in these groups not eat more than 2 servings of mercury-contaminated fish per week. Fish with the highest levels of mercury include shark, swordfish, and king mackerel. All people should avoid eating large amounts of these kinds of fish, and no one should eat these fish more frequently than once a month.
Question: What is the best summary of this passage?

A) Biomagnification can explain the process behind mercury's accumulation in fish, but its widespread nature is not yet a cause for concern.
B) Thanks to the coal industry, mercury can be found in both water and the air. Mercury has impacted the ways in which we understand toxic substances.
C) Although mercury is a toxic substance, its presence in fish along with the extensive nature of fish contamination is not a cause for concern. Consumption of mercury-contaminated fish can be regulated if necessary.
D) Recommendations regarding consumption of mercury-laden fish can vary depending on the type of fish and population groups.