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

Which of the following classes is one valid superclass of 'vesicle tethering complex'?

A. protein-containing complex
B. AMPA glutamate receptor activity
C. B cell antigen processing and presentation following pinocytosis
D. 4-hydroxy-3-methylbut-2-en-1-yl diphosphate synthase activity (ferredoxin)

Answer: protein-containing complex