Mona Co-Signs a Promissory Note with Her Daughter Beth So

Mona co-signs a promissory note with her daughter Beth so Beth can purchase her first car.Mona will be discharged from her obligation on the note:

A) if Beth pays the obligation in full under the terms of the note.
B) if the creditor extends the final due date because of allowing Beth to skip a payment in December.
C) Both of the above.
D) only if Mona dies before Beth's obligation is discharged.