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

Which of the following definitions best describes 'nucleoside diphosphate metabolic process'?

A. The chemical reactions and pathways involving organophosphates, any phosphate-containing organic compound.
B. The chemical reactions and pathways involving a nucleoside diphosphate, a compound consisting of a nucleobase linked to a deoxyribose or ribose sugar esterified with diphosphate on the sugar.
C. The chemical reactions and pathways involving ADP, adenosine 5'-diphosphate.
D. The chemical reactions and pathways involving the phosphate group, the anion or salt of any phosphoric acid.

Answer: The chemical reactions and pathways involving a nucleoside diphosphate, a compound consisting of a nucleobase linked to a deoxyribose or ribose sugar esterified with diphosphate on the sugar.