(please hurry!!) Which name best describes the process of gas exchange?

A) Oxygen diffuses into the blood at the site of the heart, and carbon dioxide diffuses into the blood at the site of the alveoli.

B) Carbon dioxide diffuses into the blood at the site of the heart, and oxygen diffuses into the blood at the site of the tissues.

C) Oxygen diffuses into the blood at the site of the alveoli, and carbon dioxide diffuses into the blood at the site of the tissue.

D) Carbon dioxide diffuses into the blood at the site of the alveoli, ad oxygen diffuses into the blood at the site of the tissue.