Which instrument is used to measure blood pressure manually?

The stethoscope is the correct instrument used to manually measure blood pressure. When measuring blood pressure manually, a healthcare provider typically uses a sphygmomanometer to inflate a cuff around the upper arm. As the cuff is deflated, the provider listens to the sounds of the blood flowing through the artery using the stethoscope placed over the brachial artery. The first sound heard represents the systolic blood pressure, while the point at which the sound disappears indicates the diastolic blood pressure.

The other options do not measure blood pressure. The Bod Pod is a device used for measuring body composition, specifically body fat and lean mass. Skinfold calipers are used to assess body fat percentage by measuring the thickness of skinfolds at specific body sites. A metronome is a device that produces a regular tick sound to help musicians keep time, and it does not have any application in measuring physiological parameters like blood pressure.