A dentists office needs to keep information about patients, the number of visits they make to the office, work that must be performed, procedures performed during visits, charges and payments for treatment, and laboratory supplies and services. Assume there is only one dentist, so there is no need to store information about the dentist in the database. There are several hundred patients. Patients make many visits, and the database should store information about the services performed during each visit and the charges for each of the services. There is a standard list of charges, kept outside the database. The office uses three dental laboratories that provide supplies and services, such as fabricating dentures. Draw a complete E-R diagram for this example.