What Was the Most Important Impact of the Hawthorne Studies

What was the most important impact of the Hawthorne studies?

A) It helped managers find the level of lighting associated with optimum productivity.
B) It showed that employees could be programmed like machines to perform simple repetitive tasks, and thus led to the development of assembly lines.
C) It changed the direction of research away from Taylor's scientific management toward the study of human-based management.
D) It showed that physical working conditions have no impact on worker productivity.