that’s a great question.
the answer is indeed inaccurate.
an oxidizing agent is a component that is getting REDUCED. (It oxidizes the other component). in order to be an oxidizing agent you need to GAIN an electron, not to lose one. as copper ions losing electrons they are getting oxidized, and by that, becomes REDUCING agents.
the right answer is indeed B, since copper ions are added in the beginning of a reaction and appears again as a product of the subsequent reaction, meaning we can ‘delete’ it in a net equation and treat it as a catalyst with the intermediate of Cu++
Isn’t Cu++ an intermediate? Choice B includes Cu++ as a catalyst though