Which of the Following Is a Major Difference Between B-DNA

Which of the following is a major difference between B-DNA and A-DNA?

A) B-DNA has a right-handed helix, A-DNA has a left-handed helix
B) B-DNA has 10 residues per helix turn while A-DNA has 9
C) B-DNA base pairs are stacked almost parallel to one another while A-DNA base pairs are significantly tilted with respect to each other
D) the major groove of A-DNA is much larger than that in B-DNA
E) none of the above