The Height of a Monument Is $20$ M a Horizontal Cross-Section at a Distance X Meters from Cross-Section

Multiple Choice

The height of a monument is $20$ m. A horizontal cross-section at a distance x meters from the top is an equilateral triangle with side $\frac{x}{4}$ meters. Find the volume of the monument.

A) $\frac{125 \sqrt{3}}{3} \mathrm{~m}^{3}$
B) $\frac{125 \sqrt{2}}{3} \mathrm{~m}^{3}$
C) $\frac{\sqrt{3}}{3} \mathrm{~m}^{3}$
D) $\frac{125 \sqrt{2}}{2} \mathrm{~m}^{3}$
E) $125 \sqrt{3} \mathrm{~m}^{3}$