The argument depends on which of the following assumptions? A. Either Virginia's claim or William's claim is correct. B. The records of the hospital where their father was born date back to 1933. C. Virginia and William know the day and the month of their father's birth. D. There are urgent practical reasons why Virginia and William must know the date of their father's birth. E. None of their other relatives knows the year in which Virginia and William's father was born.