SAT English Practice Question

A recent study found that people who regularly exercise have higher levels of self-esteem than those who do not exercise. The researchers concluded that exercise can improve a person's sense of self-worth, which can lead to increased confidence and a more positive outlook on life. However, some critics have argued that the study’s findings are inconclusive, as it’s possible that people with higher levels of self-esteem are more likely to engage in exercise in the first place. How does this passage best support the idea that the study’s findings are inconclusive?

1. A.the study did not account for the possibility that people with higher levels of self-esteem are more likely to engage in exercise.
2. B.the study did not measure the effect of exercise on people’s overall happiness.
3. C.the study did not consider the possibility that exercise can improve a person’s physical health.
4. D.the study did not use a large enough sample size to draw reliable conclusions.