C. 66 square units
Step-by-step explanation:
The area of the middle rectangle would by base × height, or y × h, or 6 × 6.
The area is 36.
The area for one triangle would 1/2 × base × height.
(But since there are two triangles to solve for, the 1/2 is not necessary, and we can just do base × height again.)
So, it would be x × h, or 5 × 6.
The area is 30.
Combine both areas to get the whole area of 66 units²