Final answer:
The expression 2^3a × 2^3b simplifies to 2^3(a+b) by adding the exponents, making option A the correct choice.
Step-by-step explanation:
To find the correct expression for 2^3a × 2^3b, we use the properties of exponents. When multiplying numbers with the same base, we simply add the exponents. Thus, we add 3a and 3b to get 3(a+b). Hence, 2^3a × 2^3b simplifies to 2^(3a+3b), which is equivalent to 2^3(a+b). Therefore, the correct answer is Option A: 2^3(a+b).