An inorganic salt $(A)$ is decomposed at about $523 \ K$ to give products $(B)$ and $(C).$ Compound $(C)$ is a liquid at room temperature and is neutral to litmus paper,while oxide $(B)$ on burning with white phosphorus,gives a dehydrating agent $(D).$ Compounds $(A)$,$(B)$,$(C)$ and $(D)$ will be identified as:

• A
  $NH_4NO_3, N_2O, H_2O, P_2O_5$
• B
  $NH_4NO_2, N_2, H_2O, P_2O_5$
• C
  $CaCO_3, CaO, H_2O, CaCl_2$
• D
  $NH_4Cl, NH_3, HCl, P_2O_5$