SAT English Practice Question

A recent study found that people who eat breakfast regularly are more likely to have a healthy weight than those who skip breakfast. However, the researchers cautioned that their findings do not prove that breakfast causes weight loss. What is the most likely reason why the researchers cautioned that their findings do not prove that breakfast causes weight loss?

1. A.a correlation does not always imply causation.
2. B.a healthy diet is more important than regular breakfast habits.
3. C.breakfast is only one factor that contributes to a healthy weight.
4. D.most people who eat breakfast regularly are already health-conscious.