Final answer:
The esophagus extends from the laryngopharynx, which is part of the pharynx responsible for the passage of food, to the cardiac sphincter, where it joins the stomach.
Step-by-step explanation:
The esophagus extends from the laryngopharynx to the cardiac sphincter, where it joins the stomach. The laryngopharynx is part of the pharynx that serves as a pathway for both food (as part of the digestive system) and air (as part of the respiratory system). This region of the pharynx connects posteriorly to the opening of the esophagus. The esophagus is a muscular tube that is responsible for carrying food from the throat down to the stomach, utilizing peristaltic movements to propel the food. The correct answer to the question is A. Laryngopharynx.