Final answer:
The simplification of the expression (2a)^3 to 8a^3 is done by applying the Power of a Product Rule, which allows the exponent to be distributed to both the coefficient and the variable.
Step-by-step explanation:
The correct answer to the question is D) Power of a Product Rule. The Power of a Product Rule states that when an entire product is raised to a power, you can distribute the exponent to both the coefficient and the variable. Thus, when cubing the expression (2a)3, we separately cube the numerical coefficient 2 and the variable a, which results in 8a3. In other words, (23)(a3) simplifies to 8a3.