In living systems molecules involved in hydrogen bonding almost always contain either oxygen or nitrogen or both.How do you explain this phenomenon?

A)Oxygen and nitrogen are elements found in both nucleic acids and proteins.
B)Oxygen and nitrogen are elements with very high attractions for their electrons.
C)Oxygen and nitrogen are elements found in fats and carbohydrates.
D)Oxygen and nitrogen were both components of gases that made up the early atmosphere on Earth.
E)Oxygen and nitrogen have valence electrons.