As of April 2016, how does the FDA regulate e-cigarettes?

The correct answer indicates that as of April 2016, the FDA began regulating e-cigarettes, marking a significant step in the wider regulation of tobacco products. Before this date, e-cigarettes and other vaping products were largely unregulated at the federal level, which allowed for a wide variety of products to enter the market without oversight. The regulations that became effective in 2016 included a prohibition on sales to minors, requiring health warnings on product packaging and advertising, and mandating that manufacturers notify the FDA before introducing new products. This change reflects the agency's commitment to addressing public health concerns related to e-cigarette use, especially among young people.

The other options imply that the FDA had no regulatory authority over e-cigarettes, only restricted sales to minors, or limited its regulation to flavored products, which do not accurately represent the regulatory framework established in 2016. The comprehensive nature of the regulations demonstrates the FDA's approach to controlling the market for e-cigarettes and ensuring safety and access standards across all tobacco products.