10. Which of the following statements about the light r reactions of photosynthesis is true? (A) There are two distinct photosystems, linked together by a mechanism similar to electron transport. (B) The source for electrons is located in the stroma of the thylakoid. (C) The Mn complex is the primary electron acceptor and is located on photosystem I. (D) The ultimate electron donor is molecular oxygen. (E) Plastoquinone is a fixed electron transporter in the system located in the inner membrane.