Final answer:
Kinsey used personal interviews to explore sexual behaviors and create the Kinsey scale, while Masters and Johnson observed sexual acts to detail the sexual response cycle.
Step-by-step explanation:
The difference between the Kinsey research and the Masters and Johnson research lies in their methodologies for collecting data on human sexuality. Alfred Kinsey collected data through personal interviews and surveys to explore the range of human sexual behavior, which led to the development of the widely known Kinsey scale of sexual orientation. In contrast, William Masters and Virginia Johnson observed actual sexual acts and physiological responses, recording variables like blood pressure and arousal during sexual activity to detail the sexual response cycle. Specifically, the correct choice is C: Kinsey collected data with personal interviews while Masters and Johnson observed sexual acts. This is a reflection of the different approaches taken by both sets of researchers. Kinsey's focus was to explore the diversity of sexual behaviors and develop a sexual orientation continuum. Masters and Johnson, on the other hand, centered their research on the physiological aspects of the sexual response cycle by directly observing and measuring the body's reactions during sexual activity.