Final answer:
The sensation of "butterflies" in the stomach when anxious about public speaking is due to the release of adrenaline, triggered by the sympathetic nervous system's fight or flight response.
Step-by-step explanation:
You experience "butterflies" in your stomach when you are anxious about giving a speech because of the release of adrenaline. This happens due to the activation of the sympathetic nervous system, which is part of the autonomic nervous system that becomes active during high-arousal or stressful situations. This response is often referred to as the "fight or flight" response, and it includes physiological changes such as increased heart rate, dilated pupils, accelerated breathing, and a surge of adrenaline. The adrenaline rush causes various effects, including the sensation of "butterflies" in the stomach as blood flow is redirected to muscles in preparation for a rapid response. Hence, the correct answer to the question is B) Release of adrenaline.