A. the amount of time they spent building the wall
I think the answer is A, when I looked at the picture and did some research, I found that the wall is 70 miles long so it's pretty obvious that they spent a lot of time making it in ancient old times.
Answer = A. After World War 1
After the end of WW1 (1918) the roaring twenties began (1920) and jazz really blew up in the united states but ended at the start of the great depression.
Pretty sure it's confidence/ self esteem
hope this helps :)
The Indian Removal Act of 1830.
This act's main reason was to remove Native American tribes to make more space for the Americans.