Answer:
D. N = w² + 8w + 12
Explanation:
The current size is w by w+4, so the area is ...
A = w(w+4)
When each dimension is increased by 2, the new size is (w+2) by (w+4+2). The latter dimension can be simplified to (w+6). Now, the new area is ...
N = (w+2)(w+6) = w² +8w +12 . . . . . . . matches choice D