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: Biochemistry
Which of the following statement regarding Nitric Oxide Synthase is TRUE? 
Select and explain. 
A. It is inhibited by Calcium, B. It accepts electrons from NADH, C. It catalyzes a dioxygenase reaction, D. It requires NADPH, FAD, FMN and Heme iron
D: It requires NADPH, FAD, FMN and Heme iron
Answer: D: It requires NADPH, FAD, FMN and Heme iron 
Explanation: Nitric oxide synthase is an enzyme required for the synthesis of nitric oxide from arginine. It is a dimeric protein and contains heme, FAD, FMN, tetrahydrobiopterin and calmodulin. This enzyme utilises molecular oxygen and NADPH. Ref: Harper's Illustrated Biochemistry, 26th Edition, Page 572; Lippincott's Biochemistry, 2nd Edition, Page 85; Textbook of Biochemistry By D M Vasudevan, 3rd Edition, Page 178