This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Massage of the carotid sinus results in all of the following, EXCEPT: 
Select and explain. 
A. Increased pressure at the carotid sinus baroreceptors, B. Decreased firing rate of the carotid sinus fibers, C. Decreased firing rate of cardiac sympathetic fibers, D. Increased firing rate of the vagus nerve
B: Decreased firing rate of the carotid sinus fibers
Answer: B: Decreased firing rate of the carotid sinus fibers 
Explanation: Increased baroreceptor pressure causes an increase in the firing rate of the carotid sinus nerve (afferent) that inhibits the medullary vasomotor center. Consequently, both a decrease in sympathetic tone and an increases in vagal discharge (efferent) contribute to the fall in hea rate and aerial blood pressure following carotid sinus massage. When performing this maneuver on your patients or peers, be prepared for cardiac sinus arrest and avoid vigorous massage, which might dislodge an embolus and cause permanent neurological damage. Ref: Essential Cardiology: Principles and Practice, 3rd Ed, page 336-337