The correct answer is: A. N2 and H2O
Ammonium nitrate is a chemical compound with the formula NH4NO3. It is a white, crystalline solid that is highly soluble in water. Ammonium nitrate is a common fertilizer and is also used in explosives.
When ammonium nitrate is heated, it decomposes into nitrogen gas and water vapor. The reaction is exothermic, meaning that it releases heat. The decomposition of ammonium nitrate is a two-step process. The first step is the formation of ammonia and nitric oxide:
$$\ce{NH4NO3(s) ->[\pu{200-250 °C}] NH3(g) + NO(g)}$$
The second step is the reaction of ammonia and nitric oxide to form nitrogen and water vapor:
$$\ce{2NH3(g) + 2NO(g) ->[\pu{450-500 °C}] N2(g) + 2H2O(g)}$$
The overall reaction is:
$$\ce{NH4NO3(s) ->[\pu{450-500 °C}] N2(g) + 2H2O(g)}$$
The decomposition of ammonium nitrate is a dangerous process. It can be triggered by heat, shock, or friction. The decomposition can produce a large amount of heat, which can cause fires and explosions. The decomposition can also produce toxic gases, such as nitrogen dioxide.