Read the rough-draft paragraph.

Since popcorn is a whole grain, it is high in dietary fiber, which helps in the regulation and maintenance of the digestive system. To maximize the healthful benefits of eating popcorn, be sure to only munch on either air-popped popcorn or kernels that have been popped using little oil. In addition to providing dietary fiber, popcorn is also a source of antioxidants. This means that like fruits and vegetables, popcorn contains compounds that can reduce or prevent certain cancers. So, not only is popcorn a tasty treat, it is also a nutritional powerhouse.

Which topic sentence should be added to this body paragraph?

Foods loaded with fiber have been known to lower the risk of heart disease.
Recent studies prove that popcorn is one of the healthiest snack choices.
Antioxidants are sought after by many health-conscious people.
Air-popping and microwaving are two methods of preparing popcorn.