Hard Research is usually conducted by whom?

Hard Research refers to research grounded in technical, scientific, engineering, technological, or intellectual-property inquiry. It is usually associated with technology research and development, patent investigation, technical feasibility, engineering experimentation, laboratory work, and scientific validation. Therefore, the people most commonly associated with conducting Hard Research are scientists and engineers. Psychiatrists and psychologists are more relevant to behavioral or human-subject research, not hard technical innovation research. Mathematicians and designers may contribute to certain innovation problems, but they do not represent the standard pairing for Hard Research. Statisticians and planners may support analysis or strategic evaluation, but they are not the primary actors for technical RandD and IP-oriented research. The correct answer is D because scientists and engineers possess the technical expertise needed to investigate technologies, materials, mechanisms, technical principles, prototypes, and feasibility questions that are central to Hard Research in innovation work.