A、The telescope. B、The harmonica. C、The piano. D、The light bulb. BWhich of the following is an invention by Franklin? 四个选项均为具体的物

Who is the most important person in the United States? Someone will say Thomas Jefferson, some will say Washington and I believe most people will say it’s Benjamin Franklin.
   Often called "the first American" and "the last universal man", Benjamin Franklin’s life covered most of the eighteenth century-- from 1706 to 1790. He was America’s first great scientist and engineer and an author and philosopher of rare wit. He was one of the first supporters of the federal system of government and one of the great educational pioneers of his day. He was a successful businessman, a believer in free enterprise, and a statesman and diplomat. He truly seemed able to do almost everything.
   Always curious, Franklin looked for easier and better ways to do things. He invented an open stove which gave more heat and wasted less fuel than a fireplace. It is still used in many places today. He also made the first pair of bifocal glasses and invented a musical instrument called the harmonica and the stepladder chair.
    Franklin was especially famous as an early experimenter in electricity. On a June day in 1752, during a thunderstorm, he flew a silken kite up into the stormy sky. As a black cloud swept across the kite, a key attached to the kite string became charged with electricity. Thus, he proved that lightning and electricity are the same. Using this knowledge, he invented the lightning rod which today protects millions of buildings from lightning.