a false belief that is firmly and consistently held despite contradictory evidence or logic is a a. delusion b. hallucination c. distortion d. loose association

The answer would be C. A delusion is an impression or belief that is fully maintained despite any contradictions or facts of reality. If someone is delusional you can show them that what they think is clearly wrong with evidence, but they will still disregard the truth. (also, delusions are typically a symptom of some type of mental disorder: for example, schizophrenia). I'm fairly sure this explanation is correct.