OE
Since the “medium ... lacked a voice,” the technology of the day prevented Lloyd from speaking on film, so the first word should be something like technological. “Technical” will do. Neither “artistic” nor “commercial” describes the limits of films that lacked a voice. The second blank requires an adjective that would explain why a character would fail to speak, perhaps something like mute. “Diffident” means something like self-effacing or very shy and very shy people are often somewhat reluctant to speak; this is the best choice. “Reluctant” is a trap answer—it does not mean reluctant to speak (the similar-sounding reticent does, and the two words are often confused). “Avant-garde” (developing new or experimental artistic concepts) does not fit the desired meaning.
Answer: A,E