Q$13.$ What is the specific gravity $(S)$ of the liquid in the left leg of the manometer tube? $($Assume ${}_{\text{w}\text{a}\text{t}\text{e}\text{r}}=9810\frac{N}{m^3}).$

a$)0\mathrm{.}90$

b$)0\mathrm{.}85$

c$)0\mathrm{.}70$

d$)0\mathrm{.}80$