A pile of coal that forms a perfect cone shape has a base area of 24 m² and a height of 15 m. Assuming the pile has 25 percent of void space, and that the density of the coal given is 1400 kg/m³, determine the mass of the coal in this pile.
A. 12,600 kg
B. 14,700 kg
C. 54,000 kg
D. 126 t
E. 168 t
Answer: D