Which of the Following Statements Concerning Carbohydrates Is Correct

Which of the following statements concerning carbohydrates is correct?

A) They are the most abundant type of biochemical substance in the human body.
B) They are all polyhydroxy aldehydes, polyhydroxyketones, or substances that yield such upon hydrolysis.
C) They can exist in left-handed and right-handed forms, with the left-handed form being dominant in nature.
D) They all have a sweet taste and therefore are also called sugars.