The neuroscientist is highly critical of the current media coverage (journals and videos) about stem cell therapy for the brain. The critic argues that the claim of being able to reproduce a new brain is extremely unlikely ("only a stroke of luck hitherto unobserved").

The blank must describe what the journals and videos are doing if they are spreading an exaggerated or false hope/claim.
- A. insanity: State of being seriously mentally ill. (Too strong; refers to the audience's state, not the information's quality.)
- B. newness: State of being new. (Too weak and irrelevant.)
- C. hallucination: Seeing or perceiving something that is not there. In a figurative sense, this refers to spreading a false or deceptive belief. (Fits the idea that the media is spreading a collective false hope about what is possible.)
- D. frenzy: A state of uncontrolled excitement or wild behavior. (Refers to the mood, not the act of deception or false belief.)
- E. cataclysm: A violent natural event or upheaval. (Irrelevant.)

In this context, hallucination is used figuratively to mean that the coverage is promoting a widespread, unfounded belief or fantasy about what stem cell therapy can achieve.

The correct choice for Blank (i) is hallucination.