Which of the following statement is incorrect?
(i) Rheumatoid arthritis is an autoimmune disease.
(ii) The use of drugs like antihistamine, adrenaline, and steroids quickly reduces the symptoms of bacterial infection.
(iii) Several genes (called cellular oncogenes) have been identified in normal cells which when activated under certain conditions, could lead to oncogenic transformation of the cells.
(iv) The vaccine also generates memory - B and T cells that recognize the pathogen quickly on subsequent exposure and overwhelm the invaders with a massive production of antibodies.