The correct option is A WBC
WBCs fight against the infections. White blood cells account for only about 1 percent of the blood but their impact is significant. White blood cells, also called leukocytes, are essential for good health and protection against illness and disease. Think of white blood cells as your immunity cells. In a sense, they are continually at war. They flow through your bloodstream to battle viruses, bacteria, and other foreign invaders that threaten your health. When your body is in distress and a particular area is under attack, white blood cells rush in to help destroy the harmful substance and prevent illness. Thus, option A is correct.