Which document specifies the frequency, size, and type of sample to be inspected?

The correct choice is the sampling plan, as this document is fundamental in quality control because it provides detailed information on how to select samples for inspection. Specifically, the sampling plan outlines the frequency of inspections, the size of the samples to be taken, and the types of samples that should be inspected. This ensures that the sampling is systematic and that the results are statistically valid, allowing for an accurate assessment of quality across production runs.

The focus on frequency ensures that inspections are conducted regularly, which is vital for maintaining consistent quality. Specifying the sample size is key to balancing practical considerations with the need for statistically significant data. Additionally, outlining the types of samples to be inspected helps ensure that all critical aspects of the product are evaluated.

Other documents like inspection guidelines or audit checklists may contain relevant information, but they do not specifically address the systematic approach needed for sampling sizes and frequencies as the sampling plan does. The quality control document is typically broader, encompassing various aspects of quality management and not just focused on sampling.