Question

The system established to maintain a balance of power between the three

Answer 1

The answer is A.

The system of checks and balances ensures that no one branch, including the legislative, executive, or judicial, does not gain too much power.

For example, congress( aka legislative branch) has the ability to make laws. However, the president(aka executive branch) can check this power by vetoing these laws.
This ensures that the president can stop laws from becoming part of the US if they feel it is unjust.