Which one of the following is the exhaust pipe emission from Fuel Cell Electric Vehicles, powered by hydrogen?

Fuel Cell Electric Vehicles (FCEVs) powered by hydrogen produce only water vapour as their exhaust emission. In a hydrogen fuel cell, hydrogen reacts with oxygen from the air through an electrochemical process: 2H₂ + O₂ → 2H₂O + electricity + heat. This makes hydrogen FCEVs zero-emission vehicles at the tailpipe, with water vapour being the only byproduct. This is one of the main environmental advantages of hydrogen fuel cell technology over internal combustion engines.