This diagram shows a silhouette of the human body showing the organs of the digestive system. Label A is pointing to one of the glands that surround the mouth. Label B is pointing to the large bean-shaped organ at the end of the esophagus. Label C is pointing to the yellowish organ that is tucked under the bean-shaped organ indicated by label C. Label D is pointing to the mass of spaghetti-like tubes in the lower part of the digestive system. Image Courtesy of 3DScience. com A doctor finds that a patient is dangerously low on certain water-soluble vitamins that the body normally absorbs from food. Based on the image above, which part of the digestive system should the doctor examine more closely? A B C D