A. The scandals associated with the Harding administration is best explained by the following statement:
"Harding's cabinet used their appointment as a way to get rich any way they could" and option B is correct.
B. The growth of economy depends upon the GDP of the nation and the trading of the stocks by public represents their paying capacity as well.
Therefore, the statement "an increase in the production of consumer goods by factories" and  " an increase in the number of stocks bought and sold by the public" both A and C are correct.
C. The Americans were growing after the war and were getting more prosperous and were independent now , so they backed off from getting involved in the conspiracies of the world.
Therefore, "As Americans became more economically prosperous and independent, they did not want to continually police the world" OPTION C is correct.
Learn more about Isolationism here:
brainly.com/question/1190697