Classify each of the following voluntary settlements as an extension, a composition, or a combination of the two.
a. Paying all creditors 30 cents on the dollar in exchange for complete discharge of the debt.
b. Paying all creditors in full in three periodic installments.
c. Paying a group of creditors with claims of $10,000 in full over 2 years and immediately paying the remaining creditors 75 cents on the dollar.