Answer: D is the answer
Step-by-step explanation:
It's B, i just took the test... So :3
The dimensions of the rectangular portion of the window should be 4 by 4.
To maximize area, we make the dimensions as close to congruent as possible. Since there will be 3 sides on the rectangular portion with a frame around them, we divide 12 by 3:
12/3 = 4
This means it should be 4 by 4.