We don’t care what kind of questions had been asked. We just want to strengthen the relationship between greater overconfidence and higher likelihood of trying to start a business.

Irrelevant. People can still be overconfident despite an accurate knowledge of the odds against them. This answer choice doesn't tell us anything about the link between being more overconfident and being more likely to start a business.

Irrelevant. The conclusion is about likelihood of attempting to start a business, not about being successful in business.

This strengthens the overall link between overconfidence and the likelihood of starting a business. We know that some of the business managers were also overconfident, so by the psychologist's conclusion, we would expect at least a few of them to have attempted to start businesses as well. Meanwhile, if only the enterpreneurs, and none of the business managers, had ever attempted to start a business, this would suggest that being an entrepreneur is what makes someone more overconfident, and not the other way around. This answer choice rules out that possibility and strengthens the psychologist's argument.

Irrelevant. The psychologist's argument doesn’t say anything about business acumen. This answer choice doesn't tell us about the relationship between overconfidence and taking the risk to start a business.