Final answer:
Post-Black Death, the shift in economic power from lords to peasants led to the growth of towns as many peasants moved to urban areas for better jobs and to demand higher wages, which also helped to undermine the feudal system. Therefore correct option is D
Step-by-step explanation:
A primary reason towns grew in importance post-Black Death is D) Shift in economic power from lords to peasants. This shift occurred because the Black Death resulted in a significant labor shortage. Consequently, peasants who remained in the countryside were able to demand higher wages and rights. At the same time, many peasants moved to towns and cities seeking better employment opportunities, enhancing the towns' economic importance and contributing to the growth of a burgeoning merchant class. This also facilitated the rise in centralized monarchical power, further contributing to the decline of feudalism.