Which best describes the overall type of art that emerged in the post-war period ?

Presuming that you are talking about post-WWI, the artist movement that came out of this was very abstract so this is when you begin to see cubism (dominated by Pablo Picasso), surrealism (Salvador Dali), and the most crazy of them all- Dadaism. These wildly abstract types of art came out of the uncertainty of war. World War I had decimated an entire generation and the total war that occurred affected everyone. The public began to question their typical values and art reflected that. If you look up some of these artistic movements, you'll see how really out-of-the-box they really were.