Grammar police! Pull over!
“Criterion” is singular, “criteria” is plural.
Lauren in her post screen shotted above references “criterion and nuances.” This is incorrect. Both need to be plural, that is: “criteria and nuances” or both need to be singular: "criterion and nuance. If you in fact are explaining a single criterion and multiple nuances, those descriptors should be in separate clauses.
If you have a single criterion by which you judge credibility, this sentence should read “…who fits this criterion…” if you have multiple criteria, the sentence should read “who fits these criteria.”
How interesting that both LK and CH misuse the word in exactly the same way.