Assertion: I2O5 is used to detect CO.
Reason : In I2O5 the oxidation number of I is 5.
(1) If both assertion and reason are true and reason is the correct explanation of assertion.
(2) If both assertion and reason are true but reason is not the correct explanation of assertion.
(3) If assertion is true but reason is false.
(4) If both assertion and reason are false.