How does a cash refund annuity differ from an installment-refund annuity?

Question:

How does a cash refund differ from an installment-refund Annuity
An annuity is a series of equal payment made at equal intervals during a period of time. In other words annuity is a contract between insurer and insurance company in which insurer make a lump-sum payment or a series of payment and, in return,...