The correct answer is D) council management system.
The type of government the city of Springfield is using is a council management system.
This system of local government combines the leadership and strong attributes of the officials that have been elected with the experience and knowledge of the local government administration.
The council prefers to hire a professional manager to administrate and supervise how the public services are delivered. The manager can offer recommendations to the council because he has enough experience in the field but the council has the last word.