Because of their high sugar content, children are no longer allowed to purchase soft drinks in school cafeterias.
Because of their high sugar content, children are no longer allowed to purchase soft drinks in school cafeterias.
The most accurate and clear construction is that school cafeterias are no longer allowed to sell soft drinks to children because of their high sugar content. This maintains the logical subject-focus relationship, emphasizing the direct ban on the sales rather than the children or the action of drinking.
Because of their high sugar content, school cafeterias are no longer allowed to sell soft drinks to children.