Explanation:

- Triangle ABC: The sides measure AB = 41 cm, BC = 28 cm, CA = 15 cm.

- Midpoints: D, E, and F are the midpoints of sides AB, BC, and CA, respectively.

- Area Relation: Triangle DEF, formed by connecting these midpoints, is similar to triangle ABC. DEF's area is 1/4 of ABC's area.

- Calculate ABC's Area: Use Heron’s Formula. The area of triangle ABC is 126 square cm.

- Area of Triangle DEF: Divide ABC’s area by 4; 126/4 = 31.5 square cm.

- The correct option is Option 3: 31.5 square cm.