The coronary vessels, unlike any other blood vessels in the body, respond to sympathetic stimulation by
Correct Answer: B
Rationale: The coronary vessels are unique because they respond to sympathetic stimulation with vasodilatation, unlike most other blood vessels which constrict. Sympathetic stimulation activates the fight-or-flight response, increasing heart rate and oxygen demand. To meet this demand, the coronary arteries dilate to supply more blood to the heart muscle. Vasoconstriction (A) is incorrect as it would reduce blood flow, countering the heart's needs during stress. Decreases in force of contractility (C) or cardiac output (D) are unrelated to the vascular response and pertain more to myocardial function, not the coronary vessels' behavior. This vasodilatation is mediated by beta-adrenergic receptors, ensuring adequate perfusion during heightened activity, making B the correct choice.