Which of the Following Research Projects Is Performed in a Field

Which of the following research projects is performed in a field setting?

A) You go into a classroom and give students a questionnaire to study the effects of management style on employee motivation.
B) You go into a fast food restaurant and give employees a questionnaire to study the effects of pay on job performance.
C) You design a special room to simulate the work conditions in a factory and manipulate lighting conditions to study the effect of light on performance.
D) Both "a" and "c" are examples of research in field settings.