Hi Vinayak,
The primary focus of the passage is on the McGurk effect, which demonstrates how visual speech cues can influence auditory perception. It’s difficult to identify the issue with Option A here: it correctly states that "visual speech mismatched with auditory speech can result in the perception of an entirely different message." This directly aligns with the findings discussed in the passage where incongruent visual speech (such as lip movements for 'ga-ga-ga' dubbed onto an auditory 'ba-ba-ba' sound) leads to the perception of 'da-da-da'. This is precisely what the McGurk effect demonstrates — the integration of visual and auditory cues in a way that alters perception. While Option D isn't entirely incorrect, it doesn't encapsulate the specific phenomenon highlighted by the researchers. The passage emphasizes how visual speech influences auditory perception to create a perceptual illusion, rather than merely focusing on the imperfect integration itself. I hope this helps!