Answer:
d. a three-branch government
Explanation:
Montesquieu lays out a system for a three-branch government such as legislative, executive and judiciary. In USA, legislative is clearly separated by executive unlike India, executive is the integral part of the legislative. Executive is highly efficient in USA, it is not limited in legislative. Judiciary is having independent nature in USA, India and so on, it is the main feature of federal government. Integrated judiciary is the feature of unitary government.