The principal buffer present in human blood is

If ${\text{K}}_{{\mathrm{a}}_1}$ and ${\text{K}}_{{\mathrm{a}}_2}$ are the dissociation constants of two acids ${\text{HA}}_1$ and ${\text{HA}}_2$, then the ratio of strengths of their solutions with equimolar concentration is _____ .

$\mathrm{A}:\sqrt{\frac{{\mathrm{K}}_{\mathrm{a}2}}{{\mathrm{K}}_{\mathrm{a}1}}} \mathrm{B}:\sqrt{{\mathrm{K}}_{\mathrm{a}1}\times {\mathrm{K}}_{\mathrm{a}2}} \mathrm{C}:\sqrt{\frac{{\mathrm{K}}_{\mathrm{a}1}}{{\mathrm{K}}_{\mathrm{a}2}}}$(Enter your correct answer as $\mathrm{A}, \mathrm{B} \mathrm{or} \mathrm{C}$)

If ${\text{K}}_1$ is ionization constant of ${\text{H}}_2\text{S}\left(\mathrm{aq}\right)\rightleftharpoons 2{\text{H}}^{+}\left(\mathrm{aq}\right)+{\text{S}}^{2-}\left(\mathrm{aq}\right)$ and ${\text{K}}_2$ is that for ${\text{H}}_2\text{S}\left(\mathrm{aq}\right)\rightleftharpoons {\text{H}}^{+}\left(\mathrm{aq}\right)+{\text{HS}}^{-}\left(\mathrm{aq}\right)$, then ionization constant of ${\text{HS}}^{-}\left(\mathrm{aq}\right)\rightleftharpoons {\text{H}}^{+}\left(\mathrm{aq}\right)+{\text{S}}^{2-}\left(\mathrm{aq}\right)$ will be equal to _____.

(A) $\frac{{\mathrm{K}}_1}{{\mathrm{K}}_2}$

(B) $\frac{{\mathrm{K}}_2}{{\mathrm{K}}_1}$

(C) $\frac{{\mathrm{K}}_1}{\left[{\mathrm{S}}^{2-}\right]}$

Enter the correct answer as A, B or C.