To Create the Illusion of Heaven Opening Up in the Glorification

To create the illusion of Heaven opening up in the Glorification of Saint Ignatius, Fra Andrea Pozzo ____.

A) painted the church's actual architecture into the vault so the roof seems to be lifting off.
B) narrowed the nave ceiling so it is difficult to see the vault.
C) widened the vault so the perspective is skewed.
D) illusionistically lowered the church's actual architecture so the roof seems to be lifting off.