The correct answer is c) ATP.
ATP, or adenosine triphosphate, serves as the main energy carrier in cells. It is often referred to as the cell’s energy currency. When a cell requires energy to perform tasks such as muscle contraction, active transport, or biosynthesis, it breaks down ATP into ADP (adenosine diphosphate) and an inorganic phosphate. This reaction releases the energy stored in the high-energy bonds of ATP, making it readily available for various cellular processes.
While NADH plays a role in energy production through cellular respiration by carrying electrons, and sucrose can provide energy when metabolized, ATP is the direct molecule that cells use to power immediate processes. Phospholipids, on the other hand, are essential components of cell membranes but do not serve as an energy source.