Studies are taking place to assess the benefits to dental health of adding fluoride to drinking water, a process known as mass medication. The Health Minister has urged consideration of fluoridation, particularly in deprived areas where dental care is poor. Fluoride can occur naturally in the water because of fluoride containing minerals. Fluoride, if in the water, improves dental health by up to 50 percent. Even so, fluoridation should not take place. A campaign leader opposed to fluoridation has spoken of her experiences of living in a fluoridated area of the USA. She experienced feelings of apathy and depression; her 2 year old son showed autistic tendencies and had white flecks on his teeth. These symptoms disappeared when they returned home from the USA. Which one of the following is an underlying assumption of the argument above?
The reported health symptoms were caused by fluoride in the water.
Mass medication is always wrong
Fluoridation is cheaper than improving dental facilities.
Fluoridation is only necessary in deprived areas
Fluoridation of water is a person's only source of fluoride.