The term 'invert sugar' refers to an equimolar mixture of

Which of the list shown below have the correct pair of the structure of alanine in $\mathrm{pH}$ ranges $2-4$ and $9-11$ is

I. ${\mathrm{H}}_3\stackrel{+}{\mathrm{N}}-\mathrm{CH}\left({\mathrm{CH}}_3\right){\mathrm{CO}}_2\mathrm{H}$

II. ${\mathrm{H}}_2\mathrm{N}-\mathrm{CH}\left({\mathrm{CH}}_3\right){\mathrm{CO}}_2^{-}$

III. ${\mathrm{H}}_3\stackrel{+}{\mathrm{N}}-\mathrm{CH}\left({\mathrm{CH}}_3\right){\mathrm{CO}}_2^{-}$

IV. ${\mathrm{H}}_2\mathrm{N}-\mathrm{CH}\left({\mathrm{CH}}_3\right){\mathrm{CO}}_2\mathrm{H}$