Example:An annuity pays $$1$ at time $2,3,4,5,7,8,$ and $9.$ Which of the follow$-$

ing does not equal the present value?

$($A$)s_4^{}{v}^6+a_3{v}^6$

$($B$)a_9-a_6+a_5-a_1$

$($C$)a_{\frac{?}{\text{b}\text{a}\text{r}}(4)}^{}{v}^2+s_3^{}{v}^9$

$($D$)v^2+v^3+v^4+v^5+v^7+v^8+v^9$