I would also go with D.) Mutually assured destruction.
This whole idea mainly started during the Cold War. The United States and Soviet Union didn't want to use their nuclear weapons because they feared that if they did, the other side would retaliate. Ultimately, both sides would lose everything.
Answer:
D. Stalin replaced Vladimir Lenin upon his death in 1924.
Answer: The manor system offered people protection.
In the manor system, peasants will be allowed to work in a land that belonged to the certain lord and require the peasants to make some contributions from the result of their works.
As a return, the Lord will provide knights to protect everyone that live in that land, including the peasants.
