I have a bone to pick with answer D). I'm not convinced that the critic thinks those artists were prophetic due to "insights into the European political situation."
Insights implies inside knowledge or special contacts, both real world examples. Prophecy implies something beyond human knowledge....there's more mystery.
I chose E) " little significance to the history of post-World War I" because of the line " i tis the very prophetic power of these artworks, and NOT their break with traditional artistic techniques, that constitutes their chief interest and value."
E) seemed the most provable. Please tell me where I went wrong? The answer boggles me.