This could be false. We don’t know anything about the subset of salespersons who are both self motivated and not highly successful. We can’t say whether or not they are well organized.

This could be false. We don’t know anything about the group of salespersons who are both well organized and not highly successful.

This must be true. This answer can be rewritten as “Well Known→ /Regret.” As shown in the diagram, by chaining the conditional claims, we see that not regretting career choices is a necessary condition of being well known.

This could be false. “/WO→R” is not a valid inference that shows up on the diagram. It could be the case that some salesperson is not well organized and also does not regret their career choice.

This could be false. (E) is an incorrect reversal of the conditional relationship. We know that all people who are highly successful do not regret their career choices. (HS→/R). (E) says “/R→HS.” This incorrectly flips the sufficient and necessary conditions.