Questions 14 -16 are based on a conversation on what the woman will do on this Saturday. You now have 15 seconds to read Questions 14 -16. Why can’t the woman miss the dentist appointment

A．Because she has changed the appointment twice before.
B．Because she is free only at that period of time.
C．Because she has got a toothache all day.
D．Because her dentist will be busy at other periods.