Final answer:
The lack of laborers in European cities post-Black Death led to weakened feudal ties and an increased importance of the merchant class, whose wealth and power grew at the expense of the nobility.
Step-by-step explanation:
The impact of the lack of laborers on the European social structure led to weakened feudal ties, as many peasants left rural areas in search of better opportunities in towns and cities, as indicated in option (d) of the 18th question. This shift in labor dynamics enhanced the status of the merchant class, as the growing economic importance of trade and commerce raised their profile in the society, while concurrently decreasing the power of the nobility, which was more linked to land and feudal privileges.
The merchant class in Northern and Central Italy, for instance, gained significant wealth and political control, which not only affected the commercial landscape but also political structures, giving merchants almost complete control of the governments of Italian city-states. The rise of the merchant class was at the expense of the landed nobility, whose wealth and power were being eclipsed by the growth in commerce and industry, particularly evident by the middle of the nineteenth century.