Joshua, a floor manager in an automotive parts manufacturing plant, noted that production declined by 15 percent during a 6-month period. In an effort to understand why, Joshua moved his office to the manufacturing floor and began periodic floor "walks" over a 3-month observation period. No changes were made to personnel or to production methods during this time. After the observation period, Joshua reexamined production figures and noted that they were at an all-time high. The upturn in production was most likely due to the

 

A. Bureaucratic phenomenon.

B. Pygmalion phenomenon.

C. Observer-expectancy theory.

D. Hawthorne effect.

E. Systems theory.