Final answer:
The question seeks to determine the equivalence of heating surface area to boiler horsepower, typically for licensing purposes. The traditional measure equates one boiler horsepower to 10 square feet of heating surface. However, the information provided focuses on the conversion of Btu to Watts, and is not directly related to the question asked.
Step-by-step explanation:
The question is asking for the calculation of boiler horsepower in relation to the heating surface for the purpose of an engineer's license classification. However, the data provided in the background information primarily deals with the energy unit of British Thermal Unit (Btu) and its relation to power measurements in Watts.
To directly answer the student's question, none of the choices provided a), b), or c) explain the calculation of boiler horsepower with respect to the heating surface. The traditionally accepted measure is that one boiler horsepower is equivalent to a heating surface of 10 square feet. However, this is not universally applied and can differ depending on the context or specific engineering standards in use.