The correct option is B Na2ZnO2
The original solution contains Zn(II) and Mn(II) ions.
Zn(II) ions react with NaOH to form soluble sodium zincate. This becomes a part of filtrate.
Zn2++2NaOH→Na2ZnO2+2H+
Mn(II) ions react with NaOH to form Mn(OH)2 which is a white solid and
changes to brown MnO2. This is retained on the filter paper.
M(II)+2NaOH→Mn(OH)2(white)+2Na+
Mn(OH)2oxidation−−−−−→MnO2(brown)+H2
HCl reacts with sodium zincate to produce a white ppt which dissolves in excess HCl.
Na2ZnO2+2HCl→Zn(OH)2↓(white)+2NaCl
Zn(OH)2+2HCl→ZnCl2+2H2O
When the residue of the filter paper is oxidized with a strong oxidizing agent, reddish violet coloured MnO−4 is obtained.
MnO22[O]−−→MnO2−4