Answer:
Letters and publications written by Nazi leaders before the Second World War.
Explanation:
This answer is correct because this historian is searching for the motives of these perpetrators, letters and publications can tell their thoughts and conversations.
Overproduction, executive inaction, ill-timed tariffs, and an inexperienced Federal Reserve all contributed to the Great Depression.
Answer:
Military action near the state and threats, along with not acknowledging Taiwan as a country, punishing those who do.
I believe the answer is d