Nicki Johnson

Nicki Johnson , a sophomore mechanical engineering student , receives a call from an insurance agent , who believes that Nicki is an older woman ready to retire from teaching . He talks to her about several annuities that she could buy that would guarantee her an annual fixed income . The annuities are as follows :
Annuity = A
Initial Payment into annuity ( at t = 0 ) = P
Amount of money received per year = M
Duration of annuity ( years ) = D
A P M D

A 50 000 8500 12
B 60 000 7000 25
C 70 000 8000 20

If Nicki could earn 11 percent on her money by placing it in a savings account , should she place it instead in any of the annuities ? Which ones , if any ? Why ?