Which one of the following machines is used by an esthetician to analyze a client's skin condition?

The Wood's Lamp is specifically designed to analyze a client’s skin condition by using ultraviolet light to reveal various skin issues that may not be visible to the naked eye. This tool helps estheticians identify problems such as pigmentation irregularities, sun damage, and certain types of bacteria or fungal infections. By illuminating the skin, the Wood's Lamp allows practitioners to see hues that indicate different skin conditions, enabling them to tailor their treatments more effectively.

Other instruments mentioned serve different purposes: the magnifying lamp enhances the view of the skin but does not analyze it in the same detailed way that the Wood's Lamp does. The ultraviolet machine is primarily used for treatments and not for analysis, while the high-frequency machine is used for treating acne and stimulating the skin but does not provide diagnostic capabilities. The specific analytical function of the Wood's Lamp makes it the appropriate choice for evaluating skin conditions in clientele.