HELP PLEASE I NEED FOR A QUIZ!

Which is a complete list of factors of each term in the expression 16a+18ab?

A.16a: 1, 2, 4, 8, 16
18ab: 1, 2, 3, 6, 9, 18

B.16a: 1, 2, 4, 8, 16, a
18ab: 1, 2, 3, 6, 9, 18, b

C.16a: 2, 4, 8, a
18ab: 2, 3, 6, 9, a, b

D.16a: 1, 2, 4, 8, 16, a
18ab: 1, 2, 3, 6, 9, 18, a, b