Which blood vessel contains blood that has high oxygen concentration, low carbon dioxide concentration, and high pressure?

Question

1. aorta
2. pulmonary artery
3. pulmonary vein
4. vena cava

I wrote the answer as 3, but is wrong. Which one is the correct answer?

Answer 1

the pulonary vein would be low pressure, it is just leaving the lung capilaries and going to the heart pump. what is the where does that blood exit the heart (high pressure)?

http://biology.about.com/od/anatomy/a/aa041207a.htm

Answer 2

4. vena cava

Answer 3

Pulmonary artery

Answer 4

B