Answer:
Option A.
Explanation:
The method by which secular aristocrats took a crucial role in deciding bishops for church services, is the right answer.
Lay investiture is represented by the performance of a religious leader (bishops particularly in medieval Europe) being designated by a secular leader to work in the Catholic Church. This produced a tremendous falling out between the Church and many officers, as it appeared in a leadership contest for Europe. The Catholic Church observed it as a method for sovereigns to possibly eliminate the grip the Church had throughout Europe. The controversy had significant results in the history of Germany and the Catholic Church.