Rapid technological advancements and growth in city populations are associated with the A. Early Republic Era
B. Civil War Era
C. Jacksonian Era
D. Industrial Revolution Era

D

Explanation:

A: Not the answer. The population was still rural, especially in the southern states.

B: Only 1/2 the country was industrialized by the time the civil war began.  The  South had not really developed her cities. It was one of her problems during the civil war. Not B.

C: Jackson is best known for his dealing with the Native Americans and the Frontier.

D: It has to be this answer. Of course before the civil war the North was well developed and had large cities. After the civil war (which is what I'm thinking of) into the 1880s to the beginning of the 1900s was when the rails were built and great fortunes in Industry were made. I'd pick D but only if it was the time I'm describing.

No other answer is completely correct. D.

answer; i believe the above statement is (true);