The answer would be b I believe
One of the main reason why more people didn't foresee the economic collapse of the 1930s is because it happened so quickly with no warning, since the US economy during the 1920s was incredibly strong and showed no signs of slowing.
A kiva is a room used by Puebloans for religious rituals and political meetings, many of them associated with the kachina belief system. Among the modern Hopi and most other Pueblo people, kivas are square-walled and underground, and are used for spiritual ceremonies
-From Wikipedia
https://en.wikipedia.org/wiki/Kiva
Throughout history, we have made lots of discoveries using energy. Before 1850, wood was our main source of fuel for heating, cooking and producing steam for powering steam engines for the railroads. Other sources of energy were water, wind, coal and some manufactured natural gas.
