Is important to cancer patients because it is a two-way fight:
A Immune system
B Antibodies
C Antigen system
D none of the above

I believe the answer is A. Immune system and B. antibodies.

Explanation:

I think this is it because cancer is caused by multiplying cells in the Immune system, and the body is at war with itself, so that's why I believe this is the answer. Also because the antigen system is blood types, and that seems kinds irrelevant to the question. Hope this helps!

the last statement is correct i.e.

when your heart is not pumping enough blood around your body because your heart is severely failing, you may need an artificial heart. an artificial heart is a mechanical device, about the size of an orange, that is connected to your heart or implanted in your chest to or replace a failing heart.

answer; /// i believe that the correct answer is (a) administrative team;