Explanation

The primary component of cooking gas is methane (CH4), but it is not a mixture of methane and oxygen. Option A lists gases that are generally not the main components of LPG/CNG used for cooking. Option B includes CO2, which is not typically part of standard cooking gas mixtures. Option D is correct because cooking gas is primarily propane or butane, or natural gas (mostly methane), but not specifically a mixture of methane and oxygen.