Which One of the Following Is the Correct Formula for the Present

Which one of the following is the correct formula for the present value of an ordinary annuity?

A) C $\times$ {{1-[1 / (1+r) ^t]} / r}
B) C $\times$ {1-[1 / (1+r) ^t]} $\times$ r
C) C $\times$ {1-[1 / (1+r) ^t]}
D) C $\times$ {{1-[1 / (1+r) ^t]} $\times$ r}
E) C $\times$ {1-[r / (1+r) ^t]}