Scientist: The FDA is yet to weigh in on the effects of electronic cigarettes on long-term health. Electronic cigarettes heat up a liquid and produce the vapor inhaled by the user. The liquid consists of vegetable glycerin and propylene glycerol at varying ratios. Artificial flavoring is also added to the liquid. Although the FDA has approved vegetable glycerin, propylene glycerol, and artificial flavors for consumption, little is known about the effects of consuming their vapors. However, electronic cigarettes do not produce tar, which is one of the most dangerous chemicals in tobacco cigarettes. Which one of the following most accurately expresses the scientist's main point? ['The FDA is inefficient and ineffective at protecting public health.', 'Although all of the information is not yet available, electronic cigarettes are promising alternatives to tobacco since the former does not produce tar.', 'Smokers should quit tobacco and start using electronic cigarettes.', 'Tar is the reason why cigarettes are unhealthy.']