The chemical formula of marsh gas (methane) is: 

We must research the provided name in accordance with IUPAC guidelines for naming substances. According to a set of guidelines, different IUPAC designations are given to organic compounds. The nomenclature and terminology for chemicals are standardised by the IUPAC. It provides us with a standardised language and nomenclature for organic compounds. The method gives compounds names based on a variety of characteristics, including the quantity of carbon atoms present, the existence of functional groups, the kind of bonding between carbon atoms, and more.

Under the IUPAC system, the following fundamental requirements must be adhered to when naming any compound:
1. Determine the compound's saturation or unsaturation: The kind of bonding between carbons determines the degree of saturation and unsaturation. Unsaturated compounds have double or triple bonds connecting the carbon atoms, whereas saturated compounds only have single bonds. The suffix "-ane" is added to the names of saturated hydrocarbons in the alkane family since they serve as the foundation for identifying organic compounds. The suffix "-ene" is used for compounds with double bonds in unsaturated hydrocarbons while "-yne" is used for compounds with triple bonds.

2. Find the parent chain, the longest continuous carbon chain: Methane (one carbon parent chain), ethane, propane, butane, pentane, hexane, heptane, octane, nonane, and decane are examples of different types of alkanes (ten carbon parent chain).

3. Find the functional groups: The functional groups are amine, aldehyde, ketone, carboxylic acid (-COOH), and alcohol (-NH₂). The names are given various prefixes and suffixes based on the functional groupings.
Methane has been given the IUPAC nomenclature. The regulations make it quite evident that it is a single carbon chain. Since carbon has a valency of 4, it is linked to 4 hydrogen atoms. Methane will thus have the chemical formula CH₄.

So, the correct answer is Option B.