Which type of gas is commonly associated with LPG?

The correct choice is butane, as it is one of the primary components of Liquefied Petroleum Gas (LPG). LPG is a mixture that typically includes propane and butane, which are both hydrocarbons used widely as fuel for heating, cooking, and in vehicles.

In the context of LPG, butane serves as an important energy source, and its properties make it particularly effective for storage and usage. Butane has a higher boiling point than propane, which is why it remains gaseous and can be utilized effectively at lower temperatures when mixed with propane.

Other gases listed in the options are not typically associated with LPG. Ethane, while it is a hydrocarbon, is not a primary component of LPG. Carbon monoxide is a toxic gas produced by incomplete combustion and is not found in appreciable amounts in LPG itself. Ammonia is a compound used primarily as a refrigerant and in fertilizers, rather than a gas associated with LPG. Hence, butane is the most relevant choice when identifying common components of LPG.