Here is a multiplication sentence:

2 × (5 × 7) = 70

Drag the numbers and the parentheses to create an equivalent multiplication sentence that illustrates the associative property of multiplication.

Step-by-step explanation:

This is the correct answer because the associative property is just moving the parentheses in order to create an equivalent equation. If you move it to the 2*5, all you do is first multiply the 2*5 and then multiply 7 which is equivalent to the equation you have.

a is the right answer