What type of test is a polysomnogram?

A polysomnogram is indeed a sleep test that evaluates the various physical factors affecting sleep. It is a comprehensive recording of the biophysiological changes that occur during sleep, including brain wave activity, blood oxygen levels, heart rate, breathing, and eye and leg movements. By analyzing these different physiological parameters, healthcare providers can diagnose sleep disorders such as sleep apnea, insomnia, and restless leg syndrome. This test is crucial for understanding how physical factors impact sleep quality and overall health, thus making option C the correct answer.