Answer:
The options are written kinda wrong, so i will answer in a kinda general way.
The associative property of multiplication tells us that the order in which we solve a multiplication does not affect the final outcome.
This can be written as:
A*(B*C) = (A*B)*C
So is exactly the same first multiplying B and C, and then do the product with A, than first multiplying A and B, and then doing the product with C.
Then the correct option would look something like:
(3*x)*y = 3*(x*y)