Milk purity is measured using:(a). Hydrometer(b). Lactometer(c). Polarimeter(d). Spectrometer

The purity of milk is typically measured using a lactometer, which is the correct answer from the options provided. A lactometer is a device used to measure the density or specific gravity of milk, which can be an indicator of its quality and purity. By comparing the density of milk to a standard scale, the lactometer can provide information about the presence of added water or other substances in the milk.