Answer:
All of them.
Explanation:
For considering the annuity formula we can determinate all the proposed factor:
C represent II the amount of each cash flow
r = represent the discopunt rate
while time or "n" represent the numebr of cashflow we have to calcualte the present value.
The timing refer wether the payment are made at the beginning or end of the period.
When made at the beginning it is an annuity-due
and the (1+r) factor multiplies the previous formula to represent the addtional period of capitalization each cashflow has or the one period less to discount for each cashflwo in cases of prresent value.