What happens when the nitrates of potassium, calcium, zinc and copper are separately heated?

• A All the nitrate will decompose to their respective metals
• B The nitrates of calcium and potassium will decomposes to their nitrites
• C Only copper nitrate decomposes to the metal
• D Only the nitrates of zinc and copper will decompose to their oxides
• E The nitrates of calcium, zinc and copper decompose to their oxides