What is the topic of the passage? [3점] The telephone has saved lives by getting rapid word of illness, injury, or famine from remote places. By joining with the elevator to make possible the multistory residence or office building, it has made possible―for better or worse―the modern city. By bringing about a quantum leap in the speed and ease with which information moves from place to place, it has greatly accelerated the rate of scientific and technological change and growth in industry. Beyond doubt it almost killed the ancient art of letter writing. It has made the waging of war chillingly more efficient than formerly. Perhaps it has prevented wars that might have arisen out of international misunderstanding caused by written communication. Or perhaps by magnifying and extending irrational personal conflicts based on voice contact, it has caused them. ⓐWhy the telephone has to be used with caution ⓑ How the telephone changed the world of business ⓒ What the telephone has done to us since its introduction ⓓ How the world moves more efficiently with the invention of 　 the telephone 전문대갤러인데 나는 a번같은데 정답이 모야?