Solution :
The Uneven cash flow is defined as the series of unequal payments which is done over a period of time. Whereas if a regular amount is to be made in a fixed period of time, that such payments are known as equal cash flows.
An annuity payments refers to the payment that is made at equal interval of times. It pays a fixed amount of payments for an individual.
In the given situations,
a). Monthly rents payment is annuity payments.
b). Uneven cash flow
c). Uneven cash flow
d). Annuity