For a firm with outstanding debt of $125,000, classify each of the following voluntary settlements as an extension, a composition, or a combination of the two.
a. Paying a group of creditors in full in four periodic installments and paying the remaining creditors in full immediately.
b. Paying a group of creditors 80 cents on the dollar immediately and paying the remaining creditors 70 cents on the dollar in two periodic installments.
c. Paying all creditors in full in 270 days.