$(10$ points$)$ A manometer is attached to a tank filled with water and air. Given the heights and specific gravities of oil and mercury, the gage pressure of the air is closest to:

$h_1=9\mathrm{.}1*cm$

$h_2=8\mathrm{.}9*cm$

$h_3=10*cm$

$S{G}_{\text{o}\text{i}\text{l}}=0\mathrm{.}86$

$S{G}_{\text{m}\text{e}\text{r}\text{c}\text{u}\text{r}\text{y}}=13\mathrm{.}6$