Final answer:
Gunpowder was the technology that proved to be the downfall of the armored knight, as it allowed armies to dismantle protective walls and reduced the effectiveness of cavalry.
Step-by-step explanation:
The technology that proved to be the downfall of the armored knight was gunpowder (option b). Gunpowder, along with firearms, transformed warfare in the late medieval period by allowing armies to dismantle protective walls of castles and cities. It reduced the effectiveness of cavalry, which were previously the most effective troops.
Gunpowder was the technology that led to the downfall of the armored knight, significantly altering medieval warfare and siege tactics, rendering traditional heavy cavalry less effective.
The technology that proved to be the downfall of the armored knight was gunpowder. The development and use of gunpowder and firearms in the late Middle Ages transformed the ways wars were fought. It particularly affected heavy cavalry, as guns could kill riders and their mounts from a distance. Gunpowder also changed siege warfare, allowing armies to breach fortifications more easily with cannons and bombards, which reduced the defensive advantage of castles. Eventually, effective rifles would come into use during the Thirty Years War, but by the end of the medieval period and the early modern era, the impact of gunpowder and firearms was clear, as they had altered the effectiveness of armored knights.