Which pair of expressions is equivalent using the Associative Property of Multiplication?

a. 4(2a ⋅ 5) = (4 ⋅ 2a) ⋅ 5
b. 4(2a ⋅ 5) = 8a ⋅ 20
C. 4(2a ⋅ 5) = (2a ⋅ 5) ⋅ 4
4. 4(2a ⋅ 5) = 4 ⋅ 2a ⋅ 5