The correct answer is B) Communication plan. The fire control plan on commercial vessels is required to include information such as the location of fire detection and alarm systems, the location of firefighting equipment, emergency escape routes, and the location of watertight doors. However, a communication plan is not a required element of the fire control plan. The other options are all required components of the fire control plan. A) Smoke detectors, C) Secondary means of escape, and D) All watertight doors must be indicated on the fire control plan as part of the vessel's fire safety systems and arrangements.