Which of the following are characteristics of perpetuity?
a. The principle amount of perpetuity is repaid as a lump-sum amount
b. A perpetuity continues for a fixed time period
c. The value of a perpetuity is calculated by dividing the payment amount by the interest rate
d. A perpetuity is a constant, infinite stream of identical cash flows
e. In a perpetuity, returns are earned in the form of a series of cash flows