I believe the answer is D: Seperation of Powers. This is the most likely answer because the constitution creates a separation of powers between the three different branches of government. The legislative branch drafts creates bills, which then are voted on by both the senate and congress, then the executive branch which is the president would sign the bill into law or veto it, (if the president vetoes a bill congress needs 2/3 of the members to override the veto). The judicial branch would then look over any bills that have been drafted to confirm that they are constitutional.