This topic examines the people of China and the building law of China. Option C: If the building materials, building components and equipment are purchased by the project contractor according to the contract, the contracting unit shall not designate the contractor to purchase the building materials, building components and equipment for the project or designate the manufacturer or supplier. Scheme D: Enterprises with different qualification levels can also form a consortium to contract. Where two or more units with different qualification levels jointly contract the project, the project shall be contracted according to the business license scope of the unit with low qualification level.