When each of the nitrates of Potassium, Magnesium and iron is heated,

• A.all the nitrates decompose to their oxides
• B.the nitrate of magnesium gives the nitrite and oxygen
• C.the nitrates of iron magnesium and iron give the oxides
• D.the nitrate of iron gives the nitrite and oxygen
• E.the nitrate of the magnesium is not decomposed