Correct option is B
The maximum allowable concentration of fluoride in drinking water, according to the World Health Organization (WHO) and various national standards, is 1.5 milligrams per liter (mg/L). Fluoride is added to drinking water to prevent tooth decay, but excessive levels can lead to dental fluorosis, which causes discoloration and damage to the teeth. The 1.5 mg/L limit is designed to maximize the dental benefits of fluoride while minimizing the risk of fluorosis.
Fluoride levels above this limit can also cause skeletal fluorosis, which affects bones and joints. Thus, maintaining fluoride concentration within this limit is crucial for public health.
