Answer:
O. By using the power of lay investiture.
Step-by-step explanation:
Lay Investiture is the system or process when the religious leaders are elected and given appointment by the rulers or monarchs of secular states or kingdoms. This allows the monarchs to have control over the religious aspect of authority instead of the papal authority appointing the smaller church leaders.
Otto I was the ruler of Germany and the Roman empire after the death of his father Henry I. He took upon himself to install the leadership of the local church. Though this was supposed to be the rights and duty of the church in appointing these local leaders, Otto's act of appointing these local leaders led to an increase in his loyal followers. This practice of investiture gained a large number of support from the Church bishops, furthering his power and leadership.