The correct options are
A MgSO4.H2O
B MgO
C MgSO4
D SO3
When Epsom salt is heated, all the above mentioned products are obtained. When it is heated at 150o C, MgSO4.H2O is obtained. When this is further heated at 200o C, MgSO4 is obtained. On further heating MgO and SO3 are obtained.
MgSO4.7H2O + (heat) = MgSO4.H2O
MgSO4.H2O + (heat) = MgSO4
MgSO4 + (heat) = MgO + SO3