Answer:
Reduced
Explanation:
NAD⁺ is an intermediate electron acceptor, acting as an oxidant (together with FAD⁺) that participates in cellular respiration as a fundamental reagent, gaining a hydrogen atom (H) in this process, becoming NADH which will later be oxidized.
This process of converting NAD⁺ to NADH (and FAD⁺ converted to FADH₂) by gaining a hydrogen atom is called reduction.