I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "From the early 12th century, French builders developed the Gothic style, marked by the use of rib vaults, pointed arches, flying buttresses, and large stained glass windows. It was used mainly in churches and cathedrals, and continued in use until the 16th century in much of Europe. Classic examples of Gothic architecture include Chartres Cathedral and Reims Cathedral in France as well as Salisbury Cathedral in England. Stained glass became a crucial element in the design of churches, which continued to use extensive wall-paintings, now almost all lost."?
A:
What might have supported the arches?