Which of the Following Is the Best Description of Decomposition

Which of the following is the best description of decomposition?

A) breaking down inorganic molecules such as carbon dioxide and water into organic molecules such as carbohydrates, lipids, and proteins
B) building organic molecules such as carbohydrates, lipids, and proteins from inorganic molecules such as carbon dioxide, water, and nitrogen-containing compounds
C) building macromolecules from smaller organic molecules
D) breaking down organic molecules into inorganic molecules
E) a process undertaken by producers in an ecosystem