The major cell infected by the HIV is:

Explanation

Option C is correct.Here are the definitions of leukocytes, monocytes, helper T-lymphocytes, and B-lymphocytes:Leukocyte: A leukocyte is a type of white blood cell that is involved in the immune system. There are five main types of leukocytes: neutrophils, eosinophils, basophils, monocytes, and lymphocytes.Monocyte: A monocyte is a type of leukocyte that is derived from bone marrow and matures in the blood. Monocytes are phagocytic cells, which means that they can engulf and destroy foreign invaders. Monocytes also produce cytokines, which are proteins that help to regulate the immune response.Helper T-lymphocyte: A helper T-lymphocyte is a type of lymphocyte that helps to coordinate the immune response. Helper T-lymphocytes produce cytokines that activate other immune cells, such as B-lymphocytes and cytotoxic T-lymphocytes. This one is the correct answer as HIV virus attack on helper T- lymphocytes and causes AIDS.B-lymphocyte: A B-lymphocyte is a type of lymphocyte that produces antibodies. Antibodies are proteins that bind to specific antigens, which are foreign substances that the body recognizes as being harmful. B-lymphocytes are activated by helper T-lymphocytes, and they then produce antibodies that help to fight infection.