Final answer:
Spanish conquistadors primarily settled in urban areas in the New World to establish Spanish presence and authority. They focused on centers of power, such as creating or enhancing cities, exemplified by the construction of Castillo de San Marcos for defense against imperial challengers.
Step-by-step explanation:
The Spanish conquistadors primarily moved to urban areas in the New World, as they were focused on establishing and maintaining Spanish presence, authority, and governance in the centers of the former empires they conquered. This involved creating colonial administrative centers, converting existing urban centers, or founding new cities altogether. For instance, the Spanish built Castillo de San Marcos for defensive purposes (option B) against imperial challengers, reflecting their focus on strategic urban locations. Their urban settlements were characterized by a mix of military, religious, and civil properties that were integral to asserting Spanish dominance in the region.