Which of the following was not true for the united states during the 1920’s?

select one:

a. there was a tremendous growth in technology and industrial output.

b. the u. s. was the most important economic power in the world.

c. led by presidents harding and coolidge americans wanted business reform.

d. the entertainment industry grew as talking movies and radio became popular.

option d is correct. corroborated sources of historical evidence   is necessary to validate a claim about an event in history.

historians tend to use written sources, but audio and visual materials as well as artifacts are important objects that supply information to modern historians.

historical sources are usually divided into two categories: primary and secondary sources. depending on the historian's intent, some sources shift their designation. determining what type of sources toimplement, and the level of credibility and reliability of those sources, is a significant step in critical thinking for the historian.

explanation:

first second and third

explanation:

4 copper and gold, the california gold rush is why im pretty sure.

that would be the steamboat because none of the other things are forms of transportation