The correct answer is D) the many different territories and peoples in Western and Central Europe.
What limited the power of political leaders in the Holy Roman Empire was the many different territories and peoples in Western and Central Europe.
The Holy Roman Empire was extremely large and this represented a major difficulty for Roman Emperors and leaders to rule such an extensive portion of land. In that vast territory, many cultures, races, and ethnicities represented major challenges to the Roman authority.
That scenario was part of the decadence of the western Roman Empire that succumbed when the barbaric and germanic tribes invaded and captured Rome.