What part of a drawing provides insight on fastener location?

The correct answer highlights the importance of the NAS symbol in conveying specific information related to fasteners. The NAS symbol, which stands for National Aerospace Standards, typically provides essential details about fastener specifications, including size, type, installation methods, and their exact location on the assembly.

When examining a blueprint or a technical drawing, the NAS symbols serve as quick references that indicate where fasteners should be placed. This is crucial for ensuring proper assembly and structural integrity of aerospace components. The use of standardized symbols helps mechanics and engineers communicate effectively about fastener requirements across various projects, facilitating quality control and compliance with industry standards.

The other choices, while important in their own contexts, do not specifically address the location of fasteners. The main title block usually contains information about the drawing, such as the project name and date. The note section offers additional instructions or clarifications but does not illustrate the exact position of fasteners. Dimension lines provide the measurements needed for assembly but do not indicate where fasteners are specifically located. Thus, the NAS symbol is uniquely suited to give insight into fastener location.