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

Which of the following definitions best describes 'alpha-D-galacturonosyl-(1->4)-D-galacturonate(2-)'?

A. Dianion of 10-formyldihydrofolic acid arising from deprotonation of both carboxylic acid functions.
B. A carbohydrate acid anion arising from deprotonation of both carboxy groups of 4-(alpha-D-galactopyranuronosyl)-D-galactopyranuronic acid; major species at pH 7.3.
C. A carbohydrate acid anion that is the conjugate base of L-rhamnonic acid; major species at pH 7.3.
D. A carbohydrate acid derivative anion that is the hexa-anion of Kdo2-lipid A arising from deprotonation of both the carboxyl and phosphate functions.

Answer: A carbohydrate acid anion arising from deprotonation of both carboxy groups of 4-(alpha-D-galactopyranuronosyl)-D-galactopyranuronic acid; major species at pH 7.3.