D. Distributive
The 3x is distributed to the k to get 3xk and then the 4 to get 12x
To distribute means to multiply it by each term in your parenthesis. A(B+C)=AB+AC
Transitive means A=B and B=C so then A=C
Commutative is A+B+C=B+C+A (switching the order)
Associative property means A+(B+C)=(A+B)+C(switching the grouping)
