Answer: Option C
:
C
We can calculate the area of this quadrilateral as the sum of the areas of two triangles taking diagonal length 25m as the base for both triangles and perpendicular length 8m as theheight of one triangle and the perpendicular length 12m as theheight of another triangle.

Area of triangle = $\frac{1}{2}\times base\times height$
Area of the first triangle = $\frac{1}{2}\times 25\times 8$
Area of the second triangle = $\frac{1}{2}\times 25\times 12$
Area of quadrilateral =Area of the first triangle +Area of the second triangle
Area of quadrilateral = $\frac{1}{2}\left(25\right)(8+12)=250m^2$