Concerned about various forms of workplace harassment, a city attorney

Just because nothing bad will happen for doing something is no reason to think people will do it. Something good needs to happen. To give an absurd example, if I tell you 'eat this piece of scrap metal, nothing bad will happen', knowing that nothing bad will happen is not going to make you any more likely to eat the metal. The same is true in this question. That there are no negative consequences for filing a false harassment claim is no reason to think false claims will be filed. There would need to be some benefit to the person filing the false claim, and I can't see what that benefit could possibly be. If the claim is false, the person filing the claim is not going to receive any kind of compensation or other benefit. There's sure to be paperwork and tribunal appearances that would consume the complainant's time. Most importantly, accusing someone of racial or sexual harassment is an extremely serious thing to do; it can very easily ruin that person's career. It's not the type of thing people do frivolously, though you'd need to assume that people would for D to be the answer here. That's why I said above that D requires one to make some absurdly cynical assumptions about human behaviour.

Further, one could easily contend that D actually strengthens the argument. Some people who are legitimate victims of harassment might, in the past, have been reluctant to pursue a claim because they were concerned they lacked the evidence to prove their case. That is, they might have been concerned that their claim woud be deemed 'invalid'. Knowing that there will be no negative consequences if they are unable to prove their case might make it more likely that these legitimate victims of harassment will file a claim. The conclusion of the passage has nothing to do with the number of claims which are actually proven or found to be valid - the conclusion is simply that more legitimate victims have come forward with their complaints. If answer D is true, it may in fact be the reason that so many new legitimate victims came forward, and rather than weaken the argument, it may actually explain why the facts presented in the argument are true.

One final point: we aren't concerned here with whether the number of legitimate complaints actually tripled. The argument is true as long as the number of legitimate complaints increased. So to weaken the argument, it is not enough only to establish that there were false claims; you'd need to establish that a full two thirds of complaints were illegitimate. That is, for D to be the answer here, the campaign publicity would need to have inspired so many false complaints as to cause the total number of complaints to triple. As I discussed above, I can't see how one could reasonably think that could be the case.

So I stand by what I said above. I think it's a very poorly contrived question; it's illogical, and requires one to introduce assumptions which I find completely unreasonable.