Henry's law constant for transferring $O_{2}$ from air into water, at room temperature, is $1.3 \dfrac{\text{mmol}}{\text{liter-atm}}$. Given that the partial pressure of $O_{2}$ in the atmosphere is $0.21$ atm, the concentration of dissolved oxygen ($\text{mg/liter}$) in water in equilibrium with the atmosphere at room temperature is
(Consider the molecular weight of $O_{2}$ as $32$ $\text{g/mol}$)
- $8.7$
- $0.8$
- $198.1$
- $0.2$