Final answer:
The three sections of the small intestine are the duodenum, jejunum, and ileum, with the duodenum involved in digestion, the jejunum in nutrient absorption, and the ileum completing the absorption process. Hence, the correct option among the given ones is Option B.
Step-by-step explanation:
The three sections of the small intestine are namely duodenum, jejunum, and ileum. The duodenum is the first section where most chemical digestion occurs. Following the duodenum, the jejunum is the second section of the small intestine, approximately 0.9 meters (3 feet) long, where the majority of nutrients are absorbed into the bloodstream. Lastly, the ileum is the third section, involving the absorption of a few remaining nutrients. The inner surfaces of both the jejunum and ileum are covered with villi, which greatly increase the surface area for nutrient absorption.
The correct answer to the question is option b, which indicates that the three sections of the small intestine are the duodenum, jejunum, and ileum.