Which two statements are true regarding working with dates?（）

A. The default internal storage of dates is in the numeric format
B. The default internal storage of dates is in the character format
C. The RR date format automatically calculates the century from the SYSDATE function and does not allow the user to enter the century
D. The RR date format automatically calculates the century from the SYSDATE function but allows the user to enter the century if required