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