B) Truman Doctrine.
I hope this answer is right.
Answer:
The introduction of American plants around the world resulted in rapid population growth in Europe.
Explanation:
The introduction of American plants including potato, tomato, maize, and tobacco and various new staple crops like maize and sweet potatoes resulted in rapid population growth in Europe.
By the 19th century, potatoes were consumed widely in Europe and became an important part of the diet in much part of Europe which leads to an estimated 25% of the population growth. Portuguese introduced Maize and cassava which replaced sorghum and millet as Africa's most important food crops.
