Which of the following is a measuring aid?

• A. Tape measure
• B. Jigs
• C. Caliper
• D. Ruler

Answer: (B)

The main idea here is that a measuring aid is something that helps ensure measurements are taken or applied consistently by providing a fixed reference or guide. A jig fits this role because it holds or guides a workpiece or cutting tool so that dimensions are reproduced accurately each time. It often includes stops or built-in references that define exact locations, making the measurement process faster and more reliable in production.

The other items are instruments used to measure directly—like a tape measure, ruler, or caliper—so they are tools for measuring themselves rather than aids that set up or constrain measurements.