Which of the following is produced during incomplete combustion?

Incomplete combustion occurs when there is not enough oxygen available for a fuel to react completely, leading to the formation of various by-products that are hazardous and potentially harmful. During this process, carbon compounds do not fully oxidize into carbon dioxide but instead generate carbon monoxide, which is a highly toxic gas. Additionally, incomplete combustion can create unburned hydrocarbons and a mix of other gases that might include particulate matter and volatile organic compounds.

This understanding of incomplete combustion underscores why the correct answer highlights carbon monoxide and hydrocarbons as by-products: they are critical indicators of improper combustion processes. Recognizing these by-products is essential for assessing the efficiency and safety of combustion systems, as their presence signals that the combustion is not achieving optimal performance.

On the other hand, the mentioned by-products of complete combustion, such as carbon dioxide and water vapor, do not represent the scenario in which oxygen is insufficient. The option regarding heat and light is relevant to any combustion process but lacks specificity tied to the consequences of incomplete combustion. The final option that includes natural gas, oxygen, and hydrogen doesn't accurately reflect the outcomes of combustion processes, as these components are typically reactants rather than products of incomplete combustion.