Answer: Option A.
Explanation:
The surface area of a right rectangular prism can be calculated with this formula:

Where "w" is the width. "l" is the lenght and "h" is the height.
We know that:

Knowing this values, we can substitute them into the formula.
Therefore we get that the surface area of a right rectangular prism is this:
![SA = 2[(6in)(9in) + (9in)(18in) +(18in)(6in)]](https://img.qammunity.org/2020/formulas/mathematics/middle-school/omkwbylm36z8mysxqh07kx5l3ggx817bjt.png)

This matches with the option A.