The
correct answer is NADH.
NAD (Nicotinamide adenine dinucleotide) is a
coenzyme which is involved in redox reactions. It is found in two forms in
cells: NAD+ which is an oxidizing form and NADH which is reduced form. NADH
is a reducing agent which donates electrons and its essential role is in the
production of energy (ATP) during the cellular respiration by the mitochondria through the electron transport
chain.
