Red Scare was the name given to the widespread fear of suspected Communists and radicals in the United States after World War I. The correct option among all the options given in the question is option "A". The first Red Scare happened in the United States during the 20th century and the reason was hyper nationalism in respect to World War I.
Technology has improved city life in more ways that can be summed up easily. The developments of running water, electricity, sewage systems, public transportation, and many others helped to make city life safer and healthier. In addition technological developments in building construction allowed for taller buildings to be built creating more space for businesses to develop and places for humans to live in cities. In recent decades environmental regulations and cleaner energy use has created healthier and more sustainable living conditions in cities.
I’m pretty sure it was Americans...I’m not sure