The correct answer is D. human relations.
The Hawthorne studies were a series of experiments conducted at the Hawthorne Works of the Western Electric Company between 1924 and 1932. The studies were conducted to investigate the relationship between working conditions and productivity. The results of the studies showed that productivity was not solely determined by working conditions, but also by social factors such as morale and employee satisfaction. The Hawthorne studies led to the development of the human relations movement in management, which emphasizes the importance of employee satisfaction and morale in increasing productivity.
Scientific management is a theory of management that emphasizes the use of scientific methods to improve efficiency. One best method of doing the work is a principle of scientific management that states that there is one best way to do each job, and that this way can be found through scientific study. Specialisation is the division of work into smaller tasks that can be performed by individual workers.
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