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

Which of the following definitions best describes 'anal fin basal cartilage'?

A. A skeletal element that is part of a limb and composed of cartilage tissue.
B. Cartilage element that lies between processes of the cleithrum and pelvic girdle in gobioid fishes. Posterodorsal to the ventral end of each cleithrum is a posteriorly projecting process. The the concept (an unpaired, median structure) forms a bridge between the processes (From Springer, 1983).
C. Cartilaginous form of a vertebral centrum, a skeletal element that functionally replaces the notochord[VSAP,modified].
D. The large cartilage of the anal fin, on which the radials articulate distally [Compagno 2001. Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Volume 2].

Answer: The large cartilage of the anal fin, on which the radials articulate distally [Compagno 2001. Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Volume 2].