Question: Classify the triangle by its sides. Choose the best answer:
$12$ m
$12$ m
$12$ m
A acute
B equilateral
C isosceles
D scalene
A triangle is shown in the upper-left/center area, with all three sides labeled $12$ m; position_hint \in \{top-left, center\}.
1. **Problem Statement:** We have a triangle with all three sides measuring $12$ meters each. We need to classify this triangle by its sides.
2. **Recall the classification rules for triangles by sides:**
- **Equilateral:** All three sides are equal.
- **Isosceles:** Exactly two sides are equal.
- **Scalene:** All three sides are different.
3. **Analyze the given triangle:**
- Side 1 = $12$ m
- Side 2 = $12$ m
- Side 3 = $12$ m
Since all three sides are equal, the triangle is equilateral.
4. **Additional note:** An equilateral triangle is also always acute, but the best classification by sides is "equilateral."
**Final answer:** B equilateral