Each of the following was a cause of urbanization in medieval europe except

a) feudal lords and knights providing increased security
b) an increase in trade as a result of the crusades
c) the growth of the merchant class and guilds
d) growing threats from northern invaders

feudal lords and knights providing increased security

Explanation:

The emergence of cities was part of the genesis of the feudal formation, its’ characteristic social division of labor, the development of commodity relations, the social and political evolution of society.

Artisan peasants who left and fled from the village settled in various places depending on the availability of favorable conditions for practicing crafts (the possibility of marketing products, proximity to sources of raw materials, relative safety, etc.). Artisans often chose as the places of their settlement precisely those points that played the role of administrative, military, and church centers in the early Middle Ages. Many of these points were fortified, which provided artisans with the necessary security. The concentration of a significant population - feudal lords with their servants and a large retinue, clergy, representatives of the royal and local administration, etc. in these centers - created favorable conditions for artisans to sell their products here.

One of the favorable factors that contributed to the development of cities were trade relations.

Among the most important factors influencing the formation, layout and appearance of medieval cities, there were wars, which lasted almost continuously, and the constant threat of attacks from their own and foreign kings, princes, feudal lords, robbers.