What is the gas filled in the sealed beam head lights?a.Oxygen gasb.Nitrogen gasc.Hydrogen gasd.Argon gas

The gas commonly filled in sealed beam headlights is typically argon gas (d.). Argon is an inert gas that does not react with the materials used in the headlight, which helps to prolong the life of the filament and maintain clarity of the lens. Sealed beam headlights are designed to provide optimal lighting while also being durable, and using argon ensures that the filament remains stable and reduces the degradation of light quality over time.

In summary, among the options provided, argon gas is the most appropriate choice for use in sealed beam headlights due to its inert properties and effectiveness in maintaining headlight performance.