You invest an amount A into an account at time0. The account is governed by a constant force of interest equal to 0.04.
At time - 4, you deposit an additional amount 3A into the account and the force of interest changes to 0.06.
Which of the following best describes your balance at time 8?
(a) A(e0.16 + 3e0.24)
(b) A(e0.32 + 3e0.24)
(c) A(e0.40 + 3e0.24)
(d) A(e0.40 + 3e0.48)
(e) None of the above