Calcium hydroxide and ammonium chloride when heated together will give an important product. This compound may be obtained dry by

• A.dissolving it in water, recrystallizing it and then drying in the oven
• B.passing it through a concentrated aqueous solution of sodium hydroxide
• C.passing it through calcium oxide
• D.passing it through concentrated sulphuric acid
• E.passing it through anhydrous calcium choride