Which of the following explains why DNA adopts the B-form under physiological conditions, while RNA often adopts an A-form helical structure?
A. DNA's deoxyribose sugar lacks a 2’-OH group, reducing steric hindrance.
B. RNA’s 2’-OH group enables more stable hydrogen bonding with complementary strands.
C. The presence of the 2’-OH group in RNA leads to steric clashes, promoting the A-form.
D. Both DNA and RNA have identical phosphate backbones, which favors different base stacking.