The correct option is 1 and 3 only because CFLs (Compact Fluorescent Lamps) convert electrical energy to light using a gas-filled tube with mercury vapour, which emits ultraviolet light when electrified, whereas LEDs (Light Emitting Diodes) produce light through electroluminescence via a semiconductor. Moreover, LEDs are significantly more energy-efficient, converting a larger percentage of electrical energy into light compared to CFLs, which waste more energy as heat. In terms of lifespan, while both are longer-lasting than traditional incandescent bulbs, LEDs typically exceed CFLs in longevity, making the second statement incorrect. This understanding of energy efficiency and technology in lighting is critical for informed choices regarding energy consumption and sustainability, relevant to the UPSC examination’s focus on environmental awareness and technological advancements.