After WWII, which synthetic fabric began appearing in casual clothing?

c. spandex

Explanation:

Spandex is a synthetic material that is quite lightweight with elastic properties which is why it is heavily used in sports.

It was invented in the 1950's which was after World War II by Joseph C. Shivers and went on to become so popular that it increasingly began to be used in casual clothing.

based on the images pictured above, the major difference between the two cathedrals: the cathedral of notre dame and the amiens cathedral, is that the cathedral of notre dame emphasizes the horizontal lines while the amiens cathedral emphasizes the vertical lines.