Pope Gregory the Great Enhanced the Position of the Papacy

Pope Gregory the Great enhanced the position of the papacy by doing all of the following except

A) Formally ending the Arian heresy through his theological arguments
B) Taking over the day to day administration of the city of Rome
C) Exerting his authority outside Italy by offering financial assistance to distant churches
D) Negotiating a truce with the Lombards to prevent a sack of Rome