In the postwar period, disillusionment influenced the work of many artists and writers, prompting them to question and examine

human progress

Explanation:

The post war period was the period between the interval that happened between World War I and World War II. The devastation that occured during World War I coupled with the Great Depression brought about suffering for the Europeans and the Americans.

During this period, disappointment influenced the work of many artists and writers as they were promptiled to question and examine the progress of human beings. This brought about the artists loss of faith in their beliefs and traditional structures. Eventually, the postwar period turned out to be very productive for the American literature.

b: the establishment clause  

b: socialism