Choice Dhoice A is the correct answer.

1. Define variables: Let $w$ be the width. Then length $l = 3w$.
2. Perimeter formula: $P = 2l + 2w$
3. Substitute: $32 = 2(3w) + 2w$
4. Simplify: $32 = 6w + 2w \rightarrow 32 = 8w$
5. Divide by 8: $w = 4$
6. Verify: Length is 12. $2(12) + 2(4) = 24 + 8 = 32$ ✓

Choice Dhoice C is incorrect because this results from $4w = 32$ (forgetting to double sides).

Choice Dhoice D is incorrect because this is the length, not the width.

Choice Dhoice B is incorrect because this is half the perimeter.