Please explain why the answer to the following question is (d).

8. Annual deposits are to be made into an investment account at the end of each year. The amount deposited will he $8000 at the end of this year, and wi11 increase by $1000 each year until a deposit of $12,000 is made. After that, the deposits will increase by $2000 a year until a deposit of $18,000 is made. Which of the following represents the present value of these deposits? (a} 70001187 + 1000[Do)d-J + 100[fa)3-| (b) 8900337 + 1000(Ia)T| + 20;(;.(;;1m)3_I (c) llamasI + mowed1 + 2000mm (d) Emmal + lMDEJdJ + momma {c} 6000 5| + 1000(Io)d| + 1mm 1%