The correct answer is D) boarding and operating procedures. All MODU (Mobile Offshore Drilling Unit) personnel should be familiar with boarding and operating procedures, as this is crucial for their safety and the proper functioning of the MODU. These procedures cover the protocols for accessing and working on the MODU, as well as the proper operation of its various systems and equipment. Familiarity with these procedures helps ensure the MODU is operated safely and in compliance with relevant regulations. The other options, while important for MODU operations, are not universally required knowledge for all MODU personnel. Maintenance schedules, fuel consumption rates, and navigational systems are more specific to certain roles and responsibilities on the MODU.