which pair of expressions is equivalent using the associative property of multiplication?

5(3a ⋅ 4) = 15a ⋅ 20

5(3a ⋅ 4) = (3a ⋅ 4) ⋅ 5

5(3a ⋅ 4) = (5 ⋅ 3a) ⋅ 4

5(3a ⋅ 4) = 5 ⋅ 3a ⋅ 4