Answer:
A. stone
Step-by-step explanation:
Medieval Gothic Cathedrals were built from iron and stone, researchers find. Using radiocarbon dating on metal found in Gothic cathedrals, an interdisciplinary team has shown, for the first time through absolute dating, that iron was used to reinforce stone from the construction phase.
Cathedral Building As an Expression of Faith
The building of monumental cathedrals in the middle ages was a reflection of faith and the channel for much of the creative energy of medieval European society. Although cathedral building was driven by religious figures or institutions, it was often a community effort.