Correct Answer: High levels of fluorides in the water

Solution : The correct option is High levels of fluorides in the water .

Dental fluorosis, commonly known as mottling of dental enamel, is a disorder induced by excessive fluoride ingestion during tooth growth. It causes tooth discolouration, white or brown patches and sometimes pitting. This is often caused by eating excessive doses of fluoride in drinking water, certain foods, or dental products during tooth growth, particularly in youth. It is a cosmetic issue from minor to severe on the degree of fluoride exposure.