Which one is an organometallic compound?
A. Lithium acetate
B. lithium methoxide
C. Lithium dimethyl amide
D. Methyl lithium

Hint:Organometallic compounds are chemical compounds that contain at least one bond between the metallic elements and carbon atom that belongs to an organic molecule. Even metalloid elements like tin, silicon, and boron are known to make organometallic compounds that are utilized in industrial chemical reactions.

Complete step by step answer:
As we know, organometallic compounds are those compounds in which metal atoms are directly bonded with C-atoms. The bond between the metal and the carbon atom is usually covalent bonding in nature. Most of the organometallic compounds exist in solid states, especially the compounds where the hydrocarbon groups are aromatic or have a ring structure. In many cases, organometallic compounds are found to be toxic to humans (especially the compounds that are volatile in nature). These compounds act as reducing agents, especially when these compounds are formed by highly electropositive metals.
Organometallic compounds contain a minimum of one bond between a carbon atom of an organic and a metal of an organic compound. Methyl lithium has a Li-C bond.
Methyllithium is a highly basic and a strong nucleophile. Compared to different synthetically important organolithium, n-butyllithium, methyllithium reacts slowly with tetrahydrofuran at room temperature. An ethereal solution of methyllithium is stable for an extended period of time.
Hence, the correct answer is option D.

Note:
We know that methyllithium is a strong base and it is highly nucleophilic due to the partial negative charge present on carbon. Therefore, it reacts towards electron acceptors and proton donors. An example of an organometallic compound wherein carbons belonging to a benzene molecule bond with chromium is illustrated above. A few more types of these compounds are Grignard reagents, tetracarbonyl nickel, and dimethyl magnesium. Also, tetrameric and hexameric forms of methyllithium have been identified using NMR and crystallography.