Which of the following is not a rare gas?

Which of the following is not a rare gas?

مندرجہ ذیل میں سے کون سا نایاب گیس نہیں ہے؟
Explanation

Ozone (O₃) is a triatomic molecule of oxygen, not a noble (rare) gas.

Radon, Xenon, and Krypton are all noble gases found in Group 18 of the periodic table.