A Research Team Found That Men Who Did Not Exercise

Multiple Choice

A research team found that men who did not exercise had a higher rate of heart disease. Which of the following explanations illustrates the third-variable problem?

A) Heart disease might make it more difficult for men to exercise.
B) The relationship between exercise and heart disease might not be causal.
C) Including men who smoke in the study might erase the relationship between exercise and heart disease.
D) Smoking might cause both heart disease and reluctance to exercise.