This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Circulation, Subject name: Physiology
Which of the following statements about healthy, intact capillaries is true? 
Select and explain. 
A. They control blood pressure., B. They are lined by a simple columnar epithelium, C. They have a smooth muscle coat., D. They inhibit clot formation.
D: They inhibit clot formation.
Answer: D: They inhibit clot formation. 
Explanation: The smooth endothelial lining of intact, healthy capillaries inhibits clot formation. They are lined by a single layer of endothelial cells They do not have a smooth muscle coat. They do not control blood pressure