Which detail from “thomas edison: the master of improvement” develops the idea that edison was an improver, not just an inventor?

“thomas edison is well known as a great inventor. however, he was also a fantastic improver.”
“however, the first electric light was actually created by chemist humphry davy forty years before edison was born.”
“edison thought that the secret to a better bulb could be found in the filament. he simply needed to figure out what type of material worked best.”
“perhaps that is why he is believed to be the genius behind the lightbulb’s creation, while the names of the true inventors are unfamiliar today.”

"Thomas Edison" is well known as a "great inventor". However, he was also a "fantastic improver" is the correct answer.

Option (a);

EXPLANATION:

Thomas Edison is believed to be a landmark of inventions.  Light bulb was already invented by 'Humphry Davy' around forty years ago even when Edison was born. But those could not be used domestically at homes in a safer way. Edison invented a practical glowing light bulb for the first time.

Many people had worked and created some of the other forms of lighting. But nothing was such that could be used at homes practically. So, Edison developed 'incandescent light bulb' that was safe, practical and economical.

it should be d or b but i'm sure it's d

answer; sutherland-differential association;