I believe it is this one: A recent report revealed that about 70 percent of American silent films are lost.
Explanation:
ALL of the other phrases revolve around that one phrase.
This one: "With the arrival of talking films in the 1920s, silent films became unprofitable.
" Has to do with silent films being lost. <em>"70 percent of American silent films are lost." </em> And so on...
Answer: The sentence that seems more proper and sums up a main idea would be, "Some films were saved, but many of them were later lost in fires caused by the nitrate in film reels."
Explanation:
This is because it explains what happened to the films and how this happened to the films.
