The correct option is
A NaNO3+NH4Cl⟶NH4NO3+NaCl△→N2O+2H2OReaction:
NaNO3+NH4CI⟶NH4NO3+NaCIΔ→N2O+2H2O+NaClThe reaction completes followed by formation of ammonium nitrate (NH4NO3) and gives nitrous oxide (N2O) when heated.
Hence, option (A) is correct.