Final answer:
The charge on radicals is generally its oxidation number. It signifies electron loss or gain and reflects the overall charge of the atom.
Step-by-step explanation:
The charge on radicals is generally its oxidation number. The oxidation number represents the total number of electrons that have been removed or added to an atom to get it into its present state. It signifies electron loss or gain and reflects the overall charge of the atom. Therefore, option b. Oxidation number; because it signifies electron loss or gain is correct.