In a mine ventilation system, the resistances of two splits A and B are 0.5 Ns²m^-8 and 2 Ns²m^-8 respectively. Combined resistance of two shafts and trunk airways is 0.7 Ns²m^-8. A quantity of 20 m³/s of air passes through split A. The total air power of the ventilation system in kW are

A. 82.9

B. 48.9

C. 24.9

D. 27.9

Answer: Option C