Why Would Saxitoxin Be Water Soluble

Why would saxitoxin be water soluble?

A) The amino and hydroxyl groups could form hydrogen bonds with water
B) The ring structures would be attracted to each other through non-polar interactions
C) Saxitoxin does not have any carbon atoms, and is therefore polar
D) Saxitoxin is an ion, which thus dissolves easily in water
E) Saxitoxin bioaccumulates up trophic levels, so it must be water soluble