The correct answer is 2) appointed his own archbishops.
What Pope Gregory VII did to change the balance of power in the medieval period was that he appointed his own archbishops.
Pope Gregory VII (1020-1085) was the pope of the Catholic Church from 1073 to 1085. He established the Gregorian Reforms to the Catholic Church that included the new canon law that governed the election of the pope via the College of Cardinals and the assurance of the moral integrity of the members of the clergy.