What is the IUPAC name for CH4?

The compound CH4 is a simple hydrocarbon consisting of one carbon atom bonded to four hydrogen atoms. According to IUPAC nomenclature rules, this specific structure is categorized under alkanes, which are saturated hydrocarbons with the general formula CnH2n+2. For CH4, when n=1, the formula yields one carbon and four hydrogens, allowing it to be named "methane." The prefix "meth-" signifies one carbon atom, and the suffix "-ane" indicates it is an alkane.

The other options refer to different hydrocarbons with larger carbon chains. Hexane contains six carbon atoms; propane has three; and butane consists of four carbon atoms. Each of these alkanes has distinct structures and names corresponding to their respective number of carbon atoms, which is why they do not apply to the formula CH4. Thus, the correct IUPAC name for CH4 is indeed methane.