Answer:
A.The reactant that reduces another atom
Step-by-step explanation:
The reasoning is reversed when it comes to oxidizing and reducing agents: Cu (s) is our reducing agent since there is a reducing agent involved in the oxidation process. We need an oxidizing agent in a reduction process, thus silver cation serves as such agent. Reactants include both reducing and oxidizing substances. As a result, a reactant with an oxidizing atom is a reducing agent.