All of the options provided contributed to the increase in population during the Middle Ages, but the primary factors were improved agricultural technology and the rise of feudalism. Improved agricultural technology, such as the use of heavy plows, improved crop rotation techniques, and the introduction of new crops, led to increased food production. This resulted in a more stable food supply, which allowed the population to grow. The rise of feudalism also played a significant role in population growth. Feudalism provided a system of land ownership and agricultural production that incentivized population growth. Serfs, who made up the majority of the population, were tied to the land they worked and were expected to produce enough food to support themselves, their lords, and other members of society. This system promoted population growth as more labor was needed to work the land and produce food. Additionally, the spread of the Church and the creation of the Holy Roman Empire also contributed to the population increase, but to a lesser extent compared to improved agricultural technology and feudalism.
