You are given a diagram of the digestive tract highlighting regions A (mouth), B (stomach), and C (large intestine). If a patient has impaired water reabsorption leading to diarrhea, which highlighted region is most likely dysfunctional? Use the process of matching function to organ to answer.

• A. Region C, the large intestine, because it primarily reabsorbs water and compacts feces before defecation
• B. All regions equally, because ingestion, digestion, absorption, and defecation share water-handling responsibilities uniformly along the GI tract
• C. Region B, the stomach, because it is the primary site of nutrient absorption including water and therefore controls stool water content
• D. Region A, the mouth, because inadequate mastication would directly cause decreased water reabsorption later in the tract

Answer: (A)