Option 1 -> Helium has high thermal conductivity causing excessive heat loss, making it less ideal for bulbs.
Option 2 -> Argon and Nitrogen are both chemically inert gases commonly used together in incandescent bulbs to prevent tungsten oxidation.
Option 3 -> Hydrogen is highly reactive and flammable, not chemically inactive, making it unsuitable for bulb filling.
Option 4 -> Hydrogen is reactive and poses safety risks; this combination is not used in standard bulbs.
Hence, Option 2 (Nitrogen and Argon) -> Argon, being a noble gas, is chemically inert and reduces tungsten evaporation at high temperatures. Nitrogen is also relatively inert and cost-effective. This combination creates an inert atmosphere that prevents oxidation of the filament and significantly prolongs bulb life -> correct