Please help me with this problem I forgot what it means.

Ahistorian is writing a book about british prime minister winston churchill. she claims that churchill was one of the earliest british leaders to realize that nazi germany was a serious threat to british security what is the best way to determine whether the historian's interpretation is valid? o a. review primary sources to see if churchill ever recorded his opinions of nazi germany. o b. find out whether the historian has written any other books about british leaders. c. analyze secondary sources summarizing the effects of nazi germany on great britain. o d. cite the historian's book in another study about important 20th- century world leaders.

Which statement best evaluates the impact of the 1929 stock market crash on europe? 1. the united states established high export tariffs to europe that reduced goods exported to germany. 2. the united states promoted domestic policy initiates that reduced jobs on american bases in europe. 3. the united states promoted isolationism that withdrew troops from europe causing germany to pay its own national defense. 4. the united states eliminated loans to europe that caused germany to default on its reparation payments to france.

What was gained through the gadsden purchase