The correct option is D All of the above.
Thermal decomposition is the process in which heat is required.
It is also known as thermolysis.
It is processed in which a compound breaks into two or more products when the heat is supplied.
All of alkaline earth metal nitrate decompose on heating
to give the oxide.
M(NO3)3→2MO+4NO2+O2
Where (M = Be, Mg, Ca, Sr, Ba)