Answer:
Option: D is the correct answer.
The product is:
D.

Explanation:
We are asked to simplify the given algebraic expression i.e. we have to find the product of two algebraic expressions, which are a polynomial in terms of "a"
As both are cubic polynomial so there product will be a six-degree polynomial.
( Since on multiplying the degree gets add up )
The expression is as follows:

We know that:

Hence we get the product as:

Hence, the product is:
