Final answer:
When a reactant is oxidized, it loses electrons, which means the reactant is undergoing oxidation. The correct answer is C) Losing electrons, oxidizing, reducing. This process is also characterized by an increase in the oxidation number while it acts as a reducing agent.
Step-by-step explanation:
If a reactant is being oxidized, then it is losing electrons.
This phenomenon is also described as increasing in oxidation state.
The correct answer to the question is C) Losing electrons, oxidizing, reducing.
When a substance loses electrons, it undergoes oxidation and is referred to as the reducing agent.
In the given example of carbon and oxygen reacting to form carbon dioxide (C (s) + O2 (g) → CO2 (g)), carbon is being oxidized by losing electrons and having its oxidation number increase from 0 to +4, while oxygen is reduced, gaining electrons and decreasing its oxidation number from 0 to -2.
Thus, a reducing agent is a substance that loses electrons, and through this process, it causes another substance to be reduced, thereby becoming oxidized itself.