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

Which of the following classes is one valid superclass of 'ajugaciliatin B'?

A. ( -)-1-hydroxybybetaochlamic acid
B. ((18)O)water
C. acetate ester
D. ( Z)-6-benzylidene-3-hydroxymethyl-1,4-dimethyl-3-methylsulfanylpiperazine-2,5-dione

Answer: acetate ester