Additive manufacturing is OA. a concept that brings product engineers, process engineers, marketers, buyers, information specialists, quality specialists, and suppliers together to design a product and the processes that will meet customer expectations. OB. the activity that decides which suppliers to use, negotiates contracts, and determines whether to buy locally OC. a term to describe the technologies that build three-dimensional (3D) objects by adding layers of material such as plastic, metal, or concrete. OD. a systematic effort to reduce the cost or improve the performance of services or products, either purchased or produced.