The correct answer is B) The steam must be directed to an area separate from the steam drum. Superheating of saturated steam can occur in a steam propulsion boiler when the steam is directed to an area separate from the steam drum, such as a superheater. This allows the steam to be heated beyond its saturation temperature, leading to superheating. Increasing the firing rate (A) or feed water flow (C) would not directly cause superheating, and the economizer (D) is not the primary factor in superheating.