Final answer:
Early American lawmakers organized the legal system with parallel state and federal structures to prevent the abuse of power, drawing on their experiences with the British monarchy and their desire for a balanced government.
Step-by-step explanation:
The early American lawmakers were motivated to create a legal system with parallel structures, namely state governments and a central government, due to several factors that were rooted in their experience with the British system and their desire for independence. The most accurate answer to the question of what motivated them is: Most had experienced and fled from abuse of power at the hands of monarchies (option a). This motivation derived from their recognition of the need to balance the powers of the various branches of government and to safeguard personal liberties.
Throughout the revolutionary period, the colonists looked at the British system, with its mix of monarchy, aristocracy, and democracy, as a model that, when functioning appropriately, could prevent tyranny. The Americans implemented a system where the legislature, executive, and judiciary shared political power, essentially creating checks and balances to prevent any one branch from becoming too powerful. Experiences such as British attempts to undermine colonial self-governance, the Proclamation of 1763, and the imposition of taxes without consent prompted many colonists to perceive a breach in the social contract, leading to a desire for a government based on the consent of the governed yet vigilant against abuses of power.