An organic compound (A) with molecular formula $ ext{C}_3 ext{H}_5 ext{N}$ on reaction with $ ext{C}_6 ext{H}_5 ext{MgBr}$ followed by hydrolysis, gives a compound (B). Compound (B) forms an orange-red precipitate with 2,4-DNP reagent and does not give iodoform test. It neither reduces Tollens' or Fehling's reagent nor does it decolourise bromine water. On drastic oxidation with chromic acid it gives a carboxylic acid (C) having molecular formula $ ext{C}_7 ext{H}_6 ext{O}_2$. Identify the compounds (A), (B) and (C). Write the reactions of compound (A) with $ ext{C}_6 ext{H}_5 ext{MgBr}$ followed by hydrolysis to give compound (B).