For which pair of the fuel gases, calorific value (C.V.) of one fuel is almost double that of the other on volume basis (i.e., kcal/Nm3) while the C.V. is same on weight basis (i.e., kcal/kg)?

A. Propane and acetylene

B. Propane and LPG

C. Sewage gas and gobar gas

D. B.F gas and coke oven gas

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