The Skeletal Nature of the Gothic Construction of St

The skeletal nature of the Gothic construction of St. Denis facilitated the:

A) installation of large windows in the shallow chapels surrounding the apse.
B) provision of more space for the church's canons.
C) addition of flying buttresses to the choir to stabilize the great hemicycle.
D) addition of a transept to the original plan.
E) addition of alternate nave piers that have cylindrical and octagonal cores.