I'm taking a test and have to guess the right answer to the question after the article. Article: Taking a picture of your tongue with a mobile phone could soon instantly tell you how healthy you are. Researchers believe the images can reveal important information about a patient's health and even give them early warning of serious illness. A team at the University of Missouri is developing a system that can analyze pictures using a 5,000-year-old Chinese principle, which is based on the flow and balance of positive and negative energies in the body, and uses the tongue as a key to learning about a person's physical health, or "zheng" according to Chinese medicine. "Within a year, our goal is to create an application for smart phones that will allow anyone to take a photo of their tongue and learn the status of their zheng," said Dong Xu, chair of MU's Computer Science Department in the College of Engineering and the co-author of the latest study. The software analyzes images based on the tongue's color and coating to distinguish between tongues showing signs of "hot" or "cold" zheng. Shades of red and yellow are associated with hot zheng, whereas a white coating on the tongue is a sign of cold zheng. "Hot and cold zheng doesn't refer directly to body temperature," said Xu, "Rather, it refers to a series of symptoms associated with the state of the body as a whole." For the study, 263 gastritis patients and 48 healthy volunteers had their tongues analyzed. The gastritis patients were classified by whether they showed infection by a certain bacteria as well as the intensity of their gastritis symptoms. In addition, most of the gastritis patients had been previously classified with either hot or cold zheng. This allowed the researchers to test the accuracy of the software's analysis. "Our software is able to classify people based on their zheng status. And as we continue to work on the software we hope to improve its ability," said another co-author Ye Duan, "Eventually everyone will be able to use this tool at home using webcams or smart phone applications, which will allow them to monitor their zheng and... Question: According to Chinese medicine, zheng refers to _ . Options: A: one's body temperature B: the physical health of a person C: the possible disease of a person D: the color and coating of one's tongue
A:
B