Correct Option: C

The concentric zone model by Burgess and Sectoral Model by Hoyt are centred around the Central Business District. On the other hand, Harris and Ullman's Multiple Nuclei City Model (1945) does not assume that cities grow around a single CBD. Alt hough the CBD is retained, additional nuclei are recognised. These three are the classic models of urban land use planning. Centripetal theory is not a theory on urban land use planning. In Newtonian mechanics, gravity provides the centripetal force responsible for astronomical orbits. A centripetal force is a force that makes a body follow a curved path. Its direction is always orthogonal to the motion of the body and towards the fixed point of the instantaneous center of curvature of the path.