Unreachable conclusion. (A) concludes that someone acted responsibly. But the principle tells us about a NECESSARY condition for acting responsibly. That allows us to prove that someone did NOT act responsibly, but it does not allow us to prove that someone DID act responsibly. (If you think it does, you’re confusing sufficient and necessary conditions.)

Unreachable conclusion. (B) concludes that someone acted responsibly. But the principle tells us about a NECESSARY condition for acting responsibly. That allows us to prove that someone did NOT act responsibly, but it does not allow us to prove that someone DID act responsibly. (If you think it does, you’re confusing sufficient and necessary conditions.)

The premises of (C) strongly suggest that Toril did not act on the basis of info she made a reasonable effort to make sure was accurate and complete. After all, she had not investigated the risks associated with th investment she made, and a reasonable effort would have required at least some investigation. Because Toril did not do what was required for acting responsibly, the principle allows us to conclude that Toril did not act responsibly.

(D) doesn’t establish that Conchita did not act on the basis of info that she made a reasonable effort to make sure was accurate and complete. We don’t know what Conchita acted on, so we can’t prove that she did not act responsibly.

Jennifer’s action is not within the domain of her professional capacity. Her decision concerns where to go on vacation. Because this is outside the realm of professional capacity, the principle does not apply.