Which of the following lists all factors of the number 18?
A. 1, 2, 3, 4, 8, 12
B. 1, 2, 3, 4, 6, 8, 11
C. 1, 2, 3, 4, 6, 8, 9, 12
D. 1, 2, 3, 6, 9, 18