The fractional distillation method is used for the separation of different gases from the air. In this method

Fractional distillation is typically used to separate distinct gases from liquid air. The primary components of air are separated using their various boiling temperatures. For the purpose of separating two or more miscible liquids that tend to boil without decomposing, fractional distillation is typically utilised.

The air that makes up Earth's atmosphere contains a variety of gases, including nitrogen, argon, carbon dioxide, and oxygen. Therefore, we must further chill the air in order to separate the air sample into its constituent parts. This additional cooling procedure is known as fractional distillation of the liquid air. Similar to the traditional distillation tube used for water purification, the air separation unit is now also necessary.

Now, the relevant boiling point, or the temperature at which a liquid turns into a gas, exists for each of the gases. If we have a random air sample, we may separate the different components of the gas by gradually chilling the sample until each component liquefies. The liquefied component then falls to the bottom of the collective vessel, where it cools more as the liquid is recovered, eventually reaching the boiling point of the following compound. Compounds like carbon dioxide are unable to liquefy. Because they have different boiling points, we may use fractional distillation to separate the various gases in the air.

Hence, the correct answer is A.