A researcher intended to find out whether job satisfaction causes improved job performance. To investigate this relation, he sent out a survey to 50 car salespersons of a national car dealership, and assessed their attitudes regarding job satisfaction. The measure of job performance in this study was the number of cars sold in a month, whereby more cars sold per month indicated greater job performance. After obtaining the data, the researcher then calculated a correlation between job satisfaction and job performance, and found that the correlation was statistically significant. He concluded that job satisfaction causes one’s level of job performance. Which of the following would help ensure that the study results were generalizable?

A. The use of a national car dealership as the data source
B. providing a narrative description of a single person/event
C. The statistical analysis does not suffice to infer causation