Oxygenated blood is transported through Arteries.

Arteries:
Arteries are blood vessels that carry oxygenated blood away from the heart to various parts of the body. They have thick, elastic walls that allow them to withstand the high pressure exerted by the pumping action of the heart. Arteries branch out into smaller vessels called arterioles, which in turn lead to even smaller vessels called capillaries.

Transportation of Oxygenated Blood:
1. Heart Pumping: The heart is responsible for pumping oxygenated blood into the arteries. During each heartbeat, the left ventricle of the heart contracts, sending a surge of oxygenated blood into the aorta, the largest artery in the body.

2. Aorta: The aorta is connected to the left ventricle of the heart and serves as the main artery. It carries oxygenated blood from the heart to the rest of the body. The aorta branches out into smaller arteries that supply blood to different organs and tissues.

3. Arteries to Organs: The smaller arteries branch out further into arterioles, which regulate blood flow to specific areas. Arterioles deliver oxygenated blood to the capillaries, which are the smallest blood vessels in the body.

4. Capillaries: Capillaries are thin-walled vessels that allow for the exchange of oxygen, nutrients, and waste products between the blood and surrounding tissues. They form a vast network throughout the body, reaching almost every cell. In the capillaries, oxygen is unloaded from red blood cells and delivered to the surrounding tissues.

5. Return of Deoxygenated Blood: After oxygen is unloaded in the capillaries, the blood becomes deoxygenated and picks up waste products, such as carbon dioxide, from the tissues. This deoxygenated blood is then transported back to the heart through a network of vessels called veins.

Conclusion:
In summary, oxygenated blood is transported through arteries, which carry the oxygen-rich blood away from the heart to various parts of the body. Arteries gradually branch out into smaller vessels called arterioles, which lead to capillaries where oxygen is delivered to the tissues.

A is correct .