Of the options given here, the best choice is A; women’s fashions.
During the 1920s, the society of the United States was undergoing some fairly significant changes. Most importantly, women were becoming much more liberated. More of them had jobs. More of them lived away from their parents. There were many more ways to have fun and more time in which to enjoy them so many women went out a lot. They were doing things that had not really been possible for women in previous years.
These new moral and manners were most clearly reflected in women’s fashions. In the 1920s, the corsets and heavy clothes that had, in a very physical way, constricted women‘s lives were gone. Now, women started wearing much shorter dresses, often without sleeves. The fabrics were very lightweight. Women could move much more easily in them. This meant that the new social freedoms that women were enjoying were also reflected in their clothes. They had more freedom in both a physical sense and a social sense.
This is why A is the best answer.