Final answer:
Methane (CH4) is considered an organic molecule because it contains carbon bonded to hydrogen, which is the primary criterion for organic compounds.
Step-by-step explanation:
Out of the compounds listed, CH4 (methane) is regarded as an organic molecule. Organic molecules are defined primarily by the presence of carbon atoms in their structure, typically bonded to hydrogen and sometimes other elements like oxygen, nitrogen, sulfur, or halogens.
Methane, CH4, is the simplest hydrocarbon, consisting of a single carbon atom bonded to four hydrogen atoms. This composition is characteristic of organic chemistry, which is the study of carbon-containing compounds. In contrast, substances such as H2O (water), NaCl (sodium chloride), and NaOH (sodium hydroxide) do not fit this criterion as they lack the carbon-hydrogen bonds that define organic molecules.