Answer: First option is correct.
Explanation:
NADH - It is used for mental alertness and clarity. It is also used in Alzheimer's disease.
It is used as a reducing agent to carry electrons
So, it is carrier of electrons.
NADH is known as electron donor because of which it is used in electron transport chain.
So, NADH - Electron carrier is correctly matched with its job description.
Hence , first option is correct.