Use the model shown to answer this question. The model represents the database used by a veterinary office. The office tracks pets, owners, office visits with treatments, and doctors. Which of the following are valid business rules represented in this model? Doctor doc_fname doc_lname doc_officeNum Pet P" pet_tagNum pet_name 04 pet_DOB treated by pet_type HI - - treats + 1 1 1 assigned to has 1 1 1 owned by 1 1 1 1 1 1 1 > is for assigned to e4 Appointment appt_date appt_time * pet_tagNum appt_examRoom owns includes Owner own_fname own_Iname own_addi own_city own_state included in own_zip Code Treatment treatment_type treatment_option O A. A Doctor must be assigned to at least 1 Pet. O B. A Pet must be assigned to a Doctor. C. A Pet may be owned by more than one Owner. O D. An Appointment may be assigned to many Doctors. O A and D above are true