Task: Class Relation Understanding (ontology: Sciences/Biology)

Which of the following classes is one valid superclass of 'positive regulation of receptor internalization'?

A. ATPase-coupled phosphate ion transmembrane transporter activity
B. 1,2,3-tribromopropane metabolic process
C. 5'-deoxynucleotidase activity
D. positive regulation of receptor-mediated endocytosis

Answer: positive regulation of receptor-mediated endocytosis