One liter of a mixture of O₂ and O₃ at NTP was allowed to react with an excess of acidified solution of KI. The iodine liberated required 80 ml of M sodium thiosulphate (Na₂S₂O₃) for titration.
A) O₂
B) O₃
C) A mixture of O₂ and O₃
D) Iodine