A disadvantage of the open-hours scheduling system is that ____. 

A. it causes problems due to broken appointments
B. the patient records must be pulled before the patients arrive
C. it still requires the use of an appointment book
D. it increases the possibility of inefficient downtime for the physician
E. patients may be irritated if they find they have the same appointment time

D. it increases the possibility of inefficient downtime for the physician
One disadvantage of the open-hours scheduling system is that if no patients come to the office during a specific period, the physician is left with inefficient downtime.