Final answer:
The correct answer is b. A field study, which examines the relationship between race and helping behaviors in a real-world setting, beyond a controlled laboratory experiment.
Step-by-step explanation:
The scenario presented in the question is an example of b. A field study. In this case, the experiment is set up in a real-world environment outside of a laboratory to investigate the relationship between race and helping behaviors. A person of a specific race (either black or white) drops papers in front of a participant to see if the participant helps. By examining the helping behavior triggered by the independent variable (the race of the person who drops the papers), one can study the differences in reactions towards different races.
The described technique contrasts with correlational research, which would look at the relationship between two variables without manipulating them. It also differs from a field survey, where researchers would typically collect data through questionnaires or interviews from participants in their natural environment.