According to paragraph 3, which of the following statements about George Eastman's innovations in photography is true? A. He introduced a paper-based photographic film that was easy for customers to develop on their own. B. He manufactured a camera that was more expensive but easier to operate than earlier cameras. C. He introduced a system in which customers could exchange defective film and cameras for new ones. D. He provided customers with the service of developing their film and reloading their cameras.