What is an oxidation-reduction reaction? What is transferred during such a reaction? a) An oxidation-reduction reaction is one in which one species loses electrons and another species gains electrons. Electrons are transferred during this process from one species to another. b) An oxidation-reduction reaction is one in which both species lose electrons. Electrons are being released during this process. c) An oxidation-reduction reaction is one in which both species gain electrons. Electrons are being released during this process. d) An oxidation-reduction reaction is one in which one species loses electrons and another species gains electrons. Ions are transferred during this process.