What was the Imperial partnership involving the Franks and the church?

What was the Imperial partnership involving the Franks and the church?
 
  A) The Frankish kings would not obey the bishop, because the Frankish kings always chose the bishop.
  B) The Frankish kings would always obey the bishop, but the Frankish kings were chosen by the bishop.
  C) The Frankish kings would rule in conjunction with the bishops as partners in warfare, government, and faith.
  D) The Frankish kings would always obey the bishop, but the Frankish kings always chose the bishop.
  E) The Frankish kings would appoint clergy, and the clergy would appoint the bishops.