In the wet tests for identification of various cations by precipitation, which transition element cation doesn't belong to group IV in qualitative inorganic analysis?

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A) : Ketoses give Seliwanoff's test faster than Aldoses.

Reason (R) : Ketoses undergo $$\beta$$-elimination followed by formation of furfural.

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

What is the correct order of acidity of the protons marked $$\mathrm{A}-\mathrm{D}$$ in the given compounds ?

Formation of photochemical smog involves the following reaction in which $$\mathrm{A}, \mathrm{B}$$ and $$\mathrm{C}$$ are respectively.

$$ \begin{aligned} & \text { i. } \mathrm{NO}_{2} \stackrel{\mathrm{h} v}{\longrightarrow} \mathrm{A}+\mathrm{B} \\ & \text { ii. } \mathrm{B}+\mathrm{O}_{2} \rightarrow \mathrm{C} \\ & \text { iii. } \mathrm{A}+\mathrm{C} \rightarrow \mathrm{NO}_{2}+\mathrm{O}_{2} \end{aligned} $$

Choose the correct answer from the options given below :