For what reason/s would an account of Russian life not surprise Americans? Answer: If the themes are familiar to Americans. Interesting things might still surprise you but familiar things don't.
Someone that draws on several sources is by definition eclectic. And the keyword is Despite. So there area claims that his philosophy does not draw on several traditions. So the claims are that his philosophy is based on a single source. Option A particular would work for the first blank but consistent does not work for the second blank.