Final answer:
The sympathetic nervous system is responsible for triggering a racing heart and rapid breathing when faced with stress, as part of the 'fight or flight' response. The correct option is a) Sympathetic.
Step-by-step explanation:
When your roommate accuses you of stealing money and you experience a racing heart and rapid breathing, it's your sympathetic nervous system that is triggered. The sympathetic nervous system is part of the larger autonomic nervous system, which operates largely below the level of consciousness and controls visceral functions. It is responsible for the 'fight or flight' response, preparing your body to respond to stressful situations by increasing things like heart rate and breathing rate and redirecting blood flow to essential areas such as muscles while decreasing functions that are non-essential at that moment, like digestion.
This response enables you to effectively deal with threats or emergencies. During the fight-or-flight response, the sympathetic nervous system triggers various physiological changes, such as increased heart rate, rapid breathing, dilation of pupils, and increased blood flow to the muscles, allowing you to react quickly and effectively to potential danger.