This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General, Subject name: Physiology
Which of the following require energy? 
Select and explain. 
A. Simple diffusion, B. Facilitated diffusion, C. Passive transport, D. Active transport
D: Active transport
Answer: D: Active transport 
Explanation: Ans: d (Active transport) Ref:Ganong, 22nd ed, p. 32The transport mechanism which requires energy is active transport. The different types of transport mechanisms are given below.Types of transport* Passive transportSimple diffusionFacilitated diffusion* Active transportSimple diffusion - along the cone gradient.No carrier involved.No energy requiredFacilitated diffusion - along the cone gradientCarrier mediatedNo energy required, bi-directionalActive transport - against the cone gradientCarrier mediatedRequire energy, unidirectional