Final answer:
The overall demographic trend reflected worsening environmental conditions and the impact of the Black Death, which led to demographic changes and migrations for better conditions.
Step-by-step explanation:
The demographic trend shown in the chart is best explained by d. worsening environmental conditions, as the early fourteenth century saw a period of lower temperatures and changes in precipitation that led to crop failures. This, followed by the Black Death in the mid-fourteenth century, caused significant population loss and forced migration in search of better living conditions. The decline of feudalism post-Black Death was hastened by peasants leaving rural areas for towns and cities in search of employment, as shown by option d. Many peasants left rural areas in search of employment in towns and cities. Additionally, the same period witnessed religious transformations and the rise of merchants due to global trade growth, indicating profound social and economic changes.