Answer:
B. Smooth muscle in the tunica media
Explanation:
Arteries contains elastic and smooth muscle fibers that helps in contraction and expansion, respectively. The smooth muscle fibers are present in the tunica intima which is the thickest and middle layer of arteries.
Connective tissues and endothelium don't play a direct role in contraction or expansion. However, elastin proteins helps in contraction.
Hope this help.
