Organic compounds are those which contain carbon and hydrogen atom .
Inorganic compounds are those which do not contain hydrogen and carbon.
1) Iron is inorganic because it does not have carbon.
2) KOH is inorganic because it does not have carbon.
3) Steroid is organic as it contains carbon.
4)olive oil is organic as it contains carbon.
Hence, we conclude that 1 , 2 are inorganic and 3 ,4 are organic.