Which one of the following is also called Stranger Gas?

1. The noble gases are a group of chemical elements with similar properties; under standard conditions, they are all odorless, colorless, monatomic gases with very low chemical reactivity. 2. Xenon (Xe) is one of these noble gases. 3. Its name comes from the Greek word 'xenos', which means 'stranger', 'foreign', or 'guest'. 4. Therefore, Xenon is also called Stranger Gas. 5. Argon and Neon are other noble gases. Nitrous oxide is N2O.