The correct answer is B) By the use of a flange type solid coupling. Flange type solid couplings are typically used to join two sections of propulsion line shafting together. This is because flange couplings provide a secure, rigid connection that can withstand the high torque and stresses experienced in a vessel's propulsion system. The flanges on each shaft section are bolted together, ensuring a strong, reliable joint. The other options are incorrect because: A) Sleeve or clamp couplings are not commonly used for propulsion shafting; C) Chain couplings are flexible and not suitable for this application; and D) Gear couplings are also a type of flexible coupling, not appropriate for joining propulsion shafts.