Where can specific information concerning pressure gauges and thermometers be found?

The correct answer is A because NSTM Chapter 504 specifically covers the maintenance, calibration, and operation of pressure gauges and thermometers used in naval applications. This chapter provides detailed procedures, technical specifications, and guidelines on how to properly utilize these instruments, ensuring accuracy and safety in their usage. Understanding this reference is crucial for machinist mates as pressure gauges and thermometers play vital roles in monitoring and controlling various systems within naval machinery.

The other chapters listed, although they cover various topics within the naval systems technical manuals (NSTM), do not specifically address pressure gauges and thermometers in the depth and detail that Chapter 504 does. Each of those chapters focuses on different aspects of naval technology and engineering practices, making them less relevant for this particular inquiry regarding pressure measurement and temperature control instruments.