The correct answer is D. The Supreme Court.
Step-by-step explanation
The Supreme Court of the Roman Republic was a group made up of eight senators who had the task of electing the main ruler, also within their function was to monitor the actions of the ruler they chose intending to limit their actions avoiding misuse of the power that was granted to him. This is a sample of the contribution to the principles of the democratic system since currently, democracy is a system of government in which the rulers are chosen using the vote, also, power is divided into three branches of power (legislative, executive, and judicial) to control that the entire system works optimally without dictatorial features. Therefore, the correct answer is D. The Supreme Court.