Question

which of the following was not an important invention of the early 20th century?
a. the cotton gin
b. the phonograph
c. the airplane
d. the electric lightbulb

Explanation:

The cotton gin was invented in 1793 (late 18th - early 19th century), not early 20th century. The phonograph was invented in 1877, the airplane in 1903, and the electric light - bulb had significant developments in the late 19th century but they all have relevance to the early 20th - century technological landscape.

Answer:

A. The cotton gin