The correct answer is actually D - Spying.
The reason why D is the correct answer is because during those times, musicians could be invited to parties, balls, and festive occasions that were hosted by one family or another family or nobility or any other important group of people who could pay them a hefty sum to tell them what another family was doing and vice versa. That is why their job offered them the opportunity to work as part-time spies.
The "boom" years of the 1920's were characterized by a growth in the use of Automobiles.
While looking at the history of the United States, the 'boom years' of the early 1920s were marked by a huge change in the way people traveled.
Personal transportation was shifting from horse-driven carriages to Automobiles, recently mass-produced by Ford.
At the time, the automobiles were a clear sign of growing economic might of the United States and the optimism of the early 1920s.
Freemasons were the members of the secret fraternal order of Free and Accepted Masons that is a worldwide secret society.
Many of the founding fathers were freemasons, like George Washington, Benjamin Franklin, Paul Revere, John Hancock, John Marshall. So nine of the 56 men that signed the Declaration of Independence were Masons and 13 of the 39 that signed the US Constitution were also masons.
