گزینههای پاسخ: I don't know, Through contact with blood of an infected person, Through contact with saliva of an infected person, Through contact with sweat of an infected person, Through contact with body fluid contaminated with blood of an infected person, 1 and 2, 1 and 3, 1 and 4, 1, 2 and 3, 1, 2, 3 and 4, 2 and 3, 2, 3 and 4, 3 and 4, 2 and 4, 1, 3 and 4, 1, 2 and 4, 2 and 6