Which of the Following Describes the Main Differences Between Fish

Which of the following describes the main differences between fish and human circulation of blood throughout the body?

A) Humans have a four-chambered heart and fish have a two-chambered heart.
B) Humans, unlike fish, must move blood from the atrium to the ventricle, which supplies the blood pressure.
C) Fish, unlike humans, must overcome a lowering of blood pressure as the blood is oxygenated before it goes directly to the systemic body.
D) A and C
E) All of the above are hurdles.