The correct option is B thicker
Arteries are large blood vessels that carry blood from the heart to all parts of the body. For the blood to reach all parts of the body, heart pumps blood at a high pressure into the arteries. Veins, on the other hand carry deoxygenated blood from various body parts to the heart. In veins, the blood flows slowly. Hence, arteries have to be thicker than veins to withstand such high pressure.