(a) : The term angina means chest pain. In this disease enough oxygen does not reach the heart muscles. The patient experiences heart pain usually in front of the chest. AB blood group person have both antigens A and B, but do not have antibodies in the plasma. Due to the presence of both the antigens, AB blood group person cannot donate blood to anyone. However, the person can receive blood from any blood group as it has no antibodies. Thus, AB blood group is a universal recipient.