To act responsibly in one's professional capacity, one must act on the basis of information that one has made a reasonable effort to make sure is accurate and complete.
Principle
To do X, one must do Y is equivalent to saying X requires Y, which is equivalent to writing X → Y.
So we could write this principle like this
Acting responsibly Acting on the basis of in your job's role → info you're reasonably sure is true / complete
But if we're savvy about Apply the Principle questions, we know we want the "judgy" term on the right. Principles are supposed to sound like, .
Since "You acted responsibly / you acted irresponsibly" is the value judgment half of this answer, we want to contrapose the rule so that it's on the right side, and will thus match the conclusion of the arguments in the answer choices.
If you weren't acting then you weren't on info you tried to → acting responsibly make sure was true in your professional and accurate capacity
Goal
Start by checking the conclusion. If it says "thus, X was not acting responsibly", then read the evidence to see it establishes that the person wasn't acting on well-verified information.
If the conclusion says anything other that "X was not acting responsibly" (or something with equivalent meaning), then get rid of it.