Boiler H.P. is defined as the ________________ ?

A. steam evaporation rate per kg of fuel fired
B. work done in evaporating 1 kg of steam per hour from and at 100°C into dry saturated steam
C. the evaporation of 15.65 kg of water per hour from and at 100°C into dry saturated steam
D. work done by 1 kg of steam at saturation condition
E. heat consumed in evaporating 1 kg water at 0°C to steam at 100°C and 1.033 kg/cm pressure