Keep on trying and you’ll find the method to the problem ____[ ]

下列各项中，没有语病的一项是（ ）

Dr. Peter Spence, _______ headmaster of the school, told us, “_______fifth of students here go on to study at Oxford and Cambridge.”

The problem is ________will go to the meeting.

I have to reschedule the appointment withyou since there is a ______ in my arrangement.