Which of the following compounds is expected to show a sharp singlet for one of its protons at δ ≥ 8 ppm in ¹H NMR spectrum, given that this signal remains unaffected on shaking the solution thoroughly with D₂O?

A. CH₃C$${\text{O}}_2^ - $$ > CH₃O^- > C₆H₅O^- > N$${\text{O}}_3^ - $$ B. CH₃O^- > N$${\text{O}}_3^ - $$ > C₆H₅O^- > CH₃C$${\text{O}}_2^ - $$ C. CH₃O^- > C₆H₅O^- > CH₃C$${\text{O}}_2^ - $$ > N$${\text{O}}_3^ - $$ D. C₆H₅O^- > CH₃O^- > N$${\text{O}}_3^ - $$ > CH₃C$${\text{O}}_2^ - $$

A. (i) peracid, (ii) H⁺, (iii) Zn/dil.HCl B. (i) Alkaline KMnO₄, (ii) NalO₄, (iii) N₂H₄/KOH C. (i) Alkaline KMnO₄, (ii) H⁺, (iii) Zn/dil.HCl D. (i) O₃/Me₂S, (ii) NaOEt, (iii) N₂H₄/KOH

A. CH₃CO₂H B. CH₃CONHC₆H₅ C. n-C₆H₁₃C ≡ CH D. n-C₆H₁₃CHO

A. reaction with sodium cyanide in the presence of nickel catalyst B. reaction with chloroform and sodium hydroxide C. diazotisation followed by reaction with CuCN D. reaction with ethyl formate followed by thermolysis