By reading and through context, my guess would be through integration.
A. China
I just googled it tbh
It was a picture of Fort Peck Dam, taken by Margaret Bourke-White.
Answer:
Austro-Hungarian
Explanation:
The Austro-Hungarian Dual Monarchy (aka Empire) disappeared entirely becoming the the nation states of, or partial nation states of, or loss of land to: Czechoslovakia, Austria, Hungary, Yugoslavia, Poland, Italy, Romania.
The answer is d and that is my opinion