To determine which molecule among the options is an organic molecule, let's analyze each option:
A. FeO - This is iron(II) oxide, an inorganic compound composed of iron and oxygen. It is commonly found in various oxidation states in minerals.
B. NaCl - This is sodium chloride, commonly known as table salt. It is an inorganic compound composed of sodium and chlorine.
C. [tex]$CH_4$[/tex] - This is methane, a compound composed of one carbon atom and four hydrogen atoms. Methane is classified as an organic molecule because it contains carbon atoms bonded to hydrogen atoms.
D. [tex]$H_2O$[/tex] - This is water, composed of two hydrogen atoms and one oxygen atom. Like FeO and NaCl, water is an inorganic compound.
Given the definitions and compositions, we can conclude that:
The organic molecule from the given options is C. [tex]$CH_4$[/tex] (methane).