Choose the Correct Answer from the List Below

Choose the correct answer from the list below. Not all of the answers will be used.
-The axis of a double helix can be twisted by a mechanism called _______________.

A) supercoiling
B) DNA
C) 5` → 3`
D) circular
E) stem loop
F) B-DNA
G) retroviruses
H) exon
I) Erwin Chargaff
J) histones
K) RNA
L) Rosalind Franklin
M) A-DNA
N) 3` → 5`