Task: Class Relation Understanding (ontology: Earth_Environment/EnvironmentOntology)

Which of the following classes is one valid superclass of 'intestinal junction'?

A. IUCN habitat/species management area
B. EC 1.14.* (oxidoreductase acting on paired donors, with incorporation or reduction of molecular oxygen) inhibitor
C. digestive tract junction
D. Bronsted acid

Answer: digestive tract junction