Using the Chen model, create an ERD that can be implemented for a medical clinic based on the following business rules: A patient can make many appointments with one or more doctors in the clinic and a doctor can accept appointments with many patients. However, each appointment is made with only one doctor, and each appointment references a single patient. Emergency cases do not require appointment. However, an emergency is entered into the appointment book as unscheduled for appointment purposes. If kept, an appointment yields a visit with the doctor specified in the appointment. The visit yields a diagnosis and, when appropriate, treatment. Each visit updates the patients records to provide medical history Each patient visit creates a bill. Each patient visit is billed by one doctor, and each doctor can bill many patients Each bill must be paid. However, a bill may be paid in many installments and payment may cover more than one bill A patient can pay the bill directly or the bill may be the basis for claim submitted to an insurance company If the bill is paid by insurance company, the deductible is submitted to an insurance company