Identify the incorrect statement about tertiary structure of proteins.

$$ \text { Given below are two statements : } $$

$$ \text { Statement I : } $$ and are two anomers of D-(+)-glucode.

Statement II : The open chain forms of D-glucose and D- fructose contain three similar chiral carbons at $\mathrm{C}_3, \mathrm{C}_4$ and $\mathrm{C}_5$.

In the light of the above statements, choose the correct answer from the options given below :

A paper dipped in a dil. $\mathrm{H}_2 \mathrm{SO}_4$ solution of ' $X$ ' upon treatment with $\mathrm{SO}_2$ gas turns into green. The compound ' $X$ ' is :

The total number of unpaired electrons present in the $d^3, d^4$ (low spin) $d^5$ (high spin), $\mathrm{d}^6$ (high spin) and $\mathrm{d}^7$ (low spin) octahedral complex systems is $\_\_\_\_$ .