What happens to iodine when iodate ions, \({\text{IO}}_3^ - \), are converted to iodine molecules, \({{\text{I}}_{\text{2}}}\)?

A.     It undergoes reduction and its oxidation number changes from \( - 1\) to 0

B.     It undergoes oxidation and its oxidation number changes from \( - 1\) to 0

C.     It undergoes reduction and its oxidation number changes from \( + 5\) to 0

D.     It undergoes oxidation and its oxidation number changes from \( + 5\) to 0

C