Tawanna is asked to find the GCF of each term in the expression 2 a b + 8 b. Her work is shown below. Factors of 2ab: 1, 2, a, and b
Factors of 8b: 1, 2, 4, 8, and b
GCF: (1) (1) (2) (2) (b) (b)

Which best describes the error in Tawanna’s solution?
Tawanna factored one or both pieces of the expression incorrectly.
Tawanna did not include each factor in the GCF.
Tawanna should have used each common factor once.
Tawanna included only one of the variables in her solution.