Answer: The correct answer is Organ system.
Esophagus, stomach, and small intestine are the different organs in the digestive system. They all function together for digesting food and absorbing nutrients out of it. This describes organ system level of organization.
Organ system can be defined as a group of organs, which work together in order to perform one more functions. The given organs are the part of the digestive system, which is an organ system. As these organs work together and digest food, which is later on absorbed in the small intestine.
Therefore, organ system level of organization is describes here.
