Organic compounds are compounds that contain carbon atoms bonded to hydrogen atoms, along with other elements such as oxygen, nitrogen, sulfur, and halogens. They are the basis of life and have a wide range of applications in various fields.

Among the given options, the correct answer is option 'D', which states that electro compounds are not a class of organic compounds. Let's understand why.

Electro compounds:
Electro compounds, also known as ionic compounds, are compounds formed by the transfer of electrons between atoms. They typically consist of metal cations and non-metal anions held together by ionic bonds. Examples of electro compounds include sodium chloride (NaCl), calcium oxide (CaO), and magnesium sulfate (MgSO4).

Explanation:

Carbonyl compounds:
Carbonyl compounds are organic compounds that contain a carbonyl group (C=O). They can be classified into two main types: aldehydes and ketones. Aldehydes have the carbonyl group at the end of a carbon chain, while ketones have it in the middle. Examples of carbonyl compounds include formaldehyde (CH2O) and acetone (CH3COCH3).

Nitro compounds:
Nitro compounds are organic compounds that contain a nitro group (NO2). They are characterized by the presence of a nitrogen atom bonded to two oxygen atoms. Nitro compounds are often used as explosives and are also found in some pharmaceuticals and dyes. Examples include nitroglycerin (C3H5N3O9) and nitrobenzene (C6H5NO2).

Amides:
Amides are organic compounds that contain a carbonyl group (C=O) bonded to a nitrogen atom. They are derived from carboxylic acids and have the general formula RCONH2. Amides are widely used in various fields, including pharmaceuticals, polymers, and agriculture. Examples include acetamide (CH3CONH2) and formamide (HCONH2).

Electro compounds:
Electro compounds, as mentioned earlier, are not organic compounds. They are formed by the transfer of electrons between atoms, typically involving metal cations and non-metal anions. These compounds do not contain carbon atoms bonded to hydrogen atoms and thus do not fall under the category of organic compounds.

In conclusion, among the given options, electro compounds (ionic compounds) are not a class of organic compounds.