A) This choice is incorrect because leukemia does not primarily affect the lymph nodes. It is a cancer of the blood and bone marrow, where abnormal white blood cells are produced.

B) This choice is incorrect because leukemia is not characterized by the overproduction of platelets. Platelets are involved in blood clotting, and their overproduction is not a feature of leukemia.

C) This choice is correct. Leukemia is a type of cancer characterized by the uncontrolled proliferation of abnormal white blood cells in the bone marrow. These abnormal cells then enter the bloodstream, crowding out healthy blood cells and impairing normal blood cell function.

D) This choice is incorrect because leukemia is not an autoimmune disorder. It is a cancerous condition involving abnormal white blood cell growth.