This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
If transport through a cell membrane requires the expenditure of energy, it is called 
Select and explain. 
A. facilitated diffusion, B. active transport, C. simple diffusion, D. All of the above
B: active transport
Answer: B: active transport 
Explanation: Active transport requires expenditure of energy to move molecules through a membrane.