Describe what happens when nad+ is reduced. what enzyme is involved?

NAD+ is a co-enzyme which function as an electron carrier. When NAD+ is reduced it receive three electron from an electron donor. Two of the electrons are positive, one is negative. These three electrons neutralize NAD+ and reduce it to NADH. The enzyme that catalyses the reaction is dehydrogenase. 

The answer to that question is a

The answer is d have a nice day