The noble people were at the top of the Confucianism four-class system.
"Uncle Sam" originally came into use during the war of 1812.
I think the answer might be a? But i'm not for sure.
Radio telegraphy
The use of radio signals to send voice and written message was discovered in the 19th century. it was necessitated by the discovery of electricity. The applications of radio signals in communications in the 21st century is of far reaching effect.
By proving the planets revolved around the sun and not the earth, thus leading to the heliocentrism